A good try, but suffers from an embarrassment of riches. What made spell books so awesome in MoM is how rare they were; you had to make real choices at creation. Finding another spell book in-game was an extremely rare event (as in, didn't happen even once in most games) that only happened upon clearing a point of interest of top-tier monsters (Sky Drakes, Demon Lords, etc).  Making it rain spell books cheapens them and reduces replay value by making most strategies available every game.  That said, it's still a nice entry into the discussion.  Tactical summons for sure are a winner.

I don't have the link to a recent SD post, but I think it was Jon who said 5 ways to win: battle, magic, diplomacy, etc.

I LOVE the idea that you can continue to grow and get more and more magic "books" or levels.  Why? Because you are able to grow and get more armies all the time, right? You're able to grow and get more diplomacy benefits, right?  You can keep growing your cities right?

The point is, to grind it in , the best game IMHO is where each strategy is balanced and allowed to keep being fresh.  If you 'max' out and can't learn more/others, then you should max out/can't add other combat units or more diplomatic relationships too.

I further would love a game where there were thousands of spells to choose from. Ever play Magic the gathering? Wow. Talk about options for strategy. You get tons of varied spells and you'll have a major milestone in an epic game. Of course it must be meaningful variation...and it can't be too overpowering.

Lastly, one of the things I liked best about MoM was that, except for the very early stages of the game, you could ALWAYS have a chance to win a battle. Because the mage was in every battle, your spells allowed you to change the course of the combat even if you were vastly outnumbered.  Buffing spells at the last second, using your summoning circle to get more units into the city just before the humongous army attacked, they add SUCH possible chances to win each battle that I cared about every unit and every combat.

You want a good game? Make it like that with updated graphics.  Guaranteed big seller. Simple as that.  Fiat.

MoM provided that through spell research, with learning vs. mana-banking being one of the primary strategic decisions. There's no reason that a MoM-like spell system need have fewer spells or a lack of growth. 

And making spell books a setup choice and very rare game reward has great fun potential. Some of my favorite MoM games were ones where I'd screwed up, gotten myself into trouble and got out because I managed to score an extra spell book and bring it into play before I lost everything. 

There are a number of factors that made MoM magic system so addicting:

- The sheer wealth of spells , 40 per magic realm

- Well named and designed spells and not mere 'fillers', very impressive considering the huge number of them

- Spell skill mechanic which limited what and how many times you can cast spells in combat, as well as limiting the speed of casting for global spells

- Randomness:

You do not know what spells will you get at the start of the game and even later in the game, you can't simply turn the spell book pages and check the names of every upcoming spell like in WoM. You can make this more predictable by investing more points on spell books of the same realm, but that still doesn't guarantee every spell and comes at the price of flexibilty [with different spell book types you have a better chance to trade spells and to conquer opposing nodes].

- Spell books are rare, really rare, as in you wont see any.

- Finally, the awesome spell research completion animated event, as opposed to a lame cheap sound effect in WoM:

http://www.youtube.com/watch?v=cL40s3T28Lo&feature=related

skip to 2:22

It gives a stronger fantasy theme, spell book is actually animated, compare to the static flash-like spell book of WoM.