Because cities (at least according to some old post) were supposed to be specialized, I suggest that the sovreign should improve A LOT the bonus given by whatever city he is in. So that the city with a wizard tower (or THE wizard tower if there is only one) could be the one improving magic, while the city with let's say the "central bank" could be improving the income... That way wizards would have a reason to move around or choose a specific bonus. Anyway I agree leaders should not be encouraged to travel like a common knight. (Just in order to annoy a few people, let me point out that such idea would obviously be spoiled once again, like most aspects of the game, by teleport)

Still this game needs lots of different strategies in order to work. There shouldn't be just ONE military strategy (IE keeping the leader in a large weapon factory to get the best weapons and such...). Take inspiration from games like Age of Wonders, where the terrain plays a major role: armies should be differentiated, by having skills that allow them to cross specific terrains or which allow the army they travel with, to do that ...by being invisible when surrounded by trees etc...

Movement is the key to strategy, don't ever think that movement is secondary to fight: when a battle takes place things are pretty much set anyways since the winner can be anticipated most of the times: strategy is mostly about getting units to the right place at the right time.

The key to variety in strategy should be the surrounding area a wizard starts with. Building the first tower will be inexpensive, but will immediately force penalties upon said wizard. It will take much longer to build this kind of building. It will change how the player plays the game. For instance, he will be rewarded with a huge advantage in spell knowledge, probably giving him and his subordinate wizards disciple level spells in every category and increased research abilities. His army gets a significant constitution and strength penalty. They will become tattered minions instead of peasants, mindless orcs instead of valiant warriors (if you are Kingdom they will be mindless brutes). Champions are impossible to predict because the information is too vague. i would want to make them be better wizards, but less capable warriors and rogues. Monsters are the hardest to predict as it is the least constant aspect of the previous game and will likely be changed drastically. I would like to see a more refined version of monsters as a resource. they should be evil, good, and neutral. if you are playing as the opposite morality, you can should be able to enslave or eradicate them or there should be some option to benefit. Being a wizard naturally lends itself to breeding powerful magical beasts. finding an area with a good beast to breed should be a significant bonus for a player or computer that favors wizard towers. Finding any magical advantage will further increase a player's desire to choose the Ivory Tower approach over say The Fellowship Of The Ring approach.

Keeping mind the new iteration of random bonus buildings, I plan to make some really overpowered level 3,4, 5 buildings to be included in the random function of building. In fact it may be that every significant tower addition is added in this way, each one shaping the form and function of one's realm. Hoping for an aviary and getting a dragon's roost would just be so sweet. The problem will be preventing a wizard from having any of the available buildings from the vanilla pool. I wonder if I can prevent them with some prerequisite. 

Exactly, the beta opens soon so I will use this thread as a note taking board for my future mod. 

This sounds like a great idea honestly. Wizard Towers were a big deal in MoM and I can see that for the inspiration for them here and to definitely help with City Specialization.

Each Improvement to your tower will give bonuses and penalties to every aspect of your nation. One option is to build the Dungeon and learn to train something better than mere men. 

Level One Dungeons

Minion Path (Leads to Conjurer Path or Beastmaster Path)

-5 to designed unit Constitution, Strength, Intelligence, and Dexterity

+5 to designed unit Spell Resistance

-80% unit upkeep cost

Level Two Dungeons

Conjurer Path

Beastmaster Path

Level Three Dungeons

Necromancy Path

Demonology Path

Serpent Path

Lycanthropy Path

Level Four Dungeons

Shadowgate Path

Hellmouth Path

Dragon King Path

Ubermeinch Path

By the end your meager Dungeon will become an terror inducing Altar of darkness. You can try to control a Shadowgate or seek out a ritual that will transform you into the God-King of Dragonkind. But beware the dangers in venturing upon sch a quest, for you may end up unleashing  terrible evil that not even you can control. 

When the time comes for modding some XML, you can call on me if you need the manpower.

Back to theory...

Level 3 Dungeons are going to focus on granting a few especially powerful creatures that can only be built in one city as well as defining the player's choice of minion to mass. Each path opens up a one per faction building that will allow a special unit or bonus. Using the one per faction ability, I can offer counters for the game's many strategies:

If you are facing an enemy that uses alot of offensive spells, you will want to build the Serpent's Lair. There you can recruit Ophies and the like to rush mages that believe themselves invincible. Any serpent you see slither about the realm can be found here. Serpents will be excellent at subverting archers and mages. Building the Serpent Temple on top of your capitol's Dungeon will also allow you to make a pact with a Great Snake. The Great Snake will be nigh unstoppable but you will only get one. Use it as a spearhead or leave it to defend during a war, just don't piss it off. 

An enemy that is relying heavily on physical damage would be better countered by delving into the realm of transmogrification. Morphing your helpless populace into werewolves to do your bidding is an oldie, but a classic. A Dark Rites Lair will confer this ability to your cities. These creatures will boast extreme healing bonuses and general resistance to most types of damage. If I can, I would prefer to allow heroes to change into creatures as well, but that will need to be looked into. At the very least they will get beastlike traits. Here your heroes will be the nigh unstoppable force. (All forces will be balanced and have their own counters.) Building a Master's Den in your capitol will allow for heroes to become something more than mere man. 

Necromancy is an ancient and highly requested art. I plan to let this path take the initiative. Why counter the tactics of the weak when you can overwhelm them with the defiled bodies of the dead? Constructing a Temple of the Undead will unlock the secrets of Necromancy for your conjurers. Armies of Skeletal Warriors and Hordes of Zombies will be your tools for destruction. It will take a very defensive strategy to build up enough of these creatures to present a serious threat to the realm, but there will be few things limiting how many damned souls you can raise from the dead. Once on the attack, every kill you make will send the soul to your capitol's Soul Tombs for conscription into your legion of the undead. You will obviously suffer drastic penalties to diplomacy once word gets out about your practices so be ready to defend your Ivory Tower. (If there is any way to have someone yell mortal combat during the random event I will make it happen.) The one pr faction building, Soul Tombs will also unlock new quests, one of which will allow you Sov to absorb souls of the fallen, conferring huge bonuses and mana gains. 

The final option will be to make a pact with the devil himself. Focusing your efforts towards demonology will reap ungodly rewards. You will be able to sacrifice your populace in trade for legions of demonic hellbeasts. This path will involve summoning demons from beyond, as well as creating mayhem by opening small rifts that will spawn beserker demons to ravage the lands. Beware though, as they will come after you as eagerly as any other. Your heroes will get special quests for cursed artifacts that have various consequences and great powers. This path will require careful diplomacy to be allowed to scour the earth for these special artifacts. You will have less power compared to other nations, but can attack indirectly and even trigger events that cause wars to weaken the strongest factions. You will also get bonuses to defense should the other factions get wise to your strategy in the form of Pit of Despair. This one per faction building will delve deep into the earth, allowing legions of demons to pour forth. You need only sacrifice a hero. 

If you need any help with learning some of the more complicated functions I can probably help. 

I think the Beastmaster path will need an entire content mod to make it a desirable option. This will be optional and modular. 

I recommend that you mod the procipinee crown to reduce EnchantmentMaintenanceMultiplier by 1, instead of being a multiplier of -100%. Then, you can use 

SetUnitStat has a higher priority than normal modifiers. The result of casting this spell, if you modded the crown like I suggested, would be that the spell costs 1 mana upkeep both for those who wear the crown, and those who don't. This effect would leak over to other enchantments. In short, your spell would be disabling the effects of the crown.

It's not perfect, but it's one solution.

Edit: I didn't actually test this, but the theory should be sound. It depends a lot on if the maintenance cost of spells is static and set when you cast a spell, or if the maintenance is automatically updated depending on if you have the crown or not.

Edit2: I'll test it quickly, I have some test items set up so it will be quick

That is a clever way to make enchantment mods modular. Nice work. I just got done with a solid magic start game as Procipene and specifically gave her every enchantment. She was a powerhouse as the game went on. It's funny, the subtle differences to making an ability -1 or -100%. 

One thing we could do with some really powerful summons is make them cost more than one mana per turn, but allow the Summoner's Path to eventually reduce the cost by 75%. This would be great for dragons and death demons, preventing the player from being able to get too many unless the correct path is chosen. 

The Ivory Towers Mod is hoping to decrease the cost of casting the spell itself. So they should function in separate areas. 

I am going to make some quests today for this mod. I will send you the result so you can see how I am framing a quest that opens up a new summons spell.