Yeah, agree on the Caravans.  I'm not even sure what effect killing an enemy's caravan has on their finances.

As for the Backswing, I understand how backswing operates, but I just don't see that it should also function on the miss of another "special" ability.  Not a big deal, but it felt a bit excessive in view of how strong Juggernauts are in the game when they start appearing.

I really hope they address the summoning tree soon.

They altered Maul in 1.3, it seems less OP than before.  Seems fine to me now no more OP than "crushing blow"

Ice elementals (automatically slow attacked enemy units) and air elementals (awesome initative, can knock over units) are great army boosters early and mid game. What most people miss about summoned units in the late game is that it's much more effective to summon them tactically. This is mainly because it gives you an extra unit in a full stack, but there are other reasons:

1) Summon them where you want on the map, e.g. next to the enemy's ranged units

2) With Mantle of Oceans etc. the mana cost is low

3) Quite often if your mage is getting summoning bonuses as they go up levels then you summon a new one at a higher level than if you let them gain experience

4) Perhaps most importantly, many have effects if you summon them tactically. This is most dramatic with Grave Elemental, which gives Death Ward to every unit within one tile. This won me a battle against dragons once, when effectively I nearly doubled the size of my army; a: move as many units around one tile as possible b: summon grave elemental in the empty tile, giving resurrection to up to six units c: get grave elemental to cast death ward on a unit which didn't get it first time around. The dragons then had to basically kill my army twice, which gave me enough time to kill them once.

I'm not a huge fan of earth elementals because they're too slow, but again, the ability to summon them tactically next to a dangerous unit (which will then concentrate its attacks on the earth elemental) can be helpful. Cragspawn are weak units for how late in the tree you get them, however the tactical summons effect of mud on all the tiles around them can be used to slow down attacking enemy melee units.

I agree though, the fire line of summoning is rubbish. Summon the Pyre of Man probably wins my prize for least cost effective spell in the entire game; the mana cost is ludicrous for a unit which disappears very quickly.

It seems to me, they designed this with another line of reasoning/thinking.  as in something like "well at least let's have them kill the weakest link so that something is gonna die instead of targeting the strongest and maybe not doing much damage on it while getting pounded by the smaller things."  The defensive thing with that is you can throw some junk units and they occupy the AI while you pound on them with your worthwhile units.

Also with the AI valuing metal at 0, it only seems to do this if it thinks it has "enough" metal. I've seen it do the same thing and I've seen it also occasionally value crystal at 0 if it has a large surplus.

Well, not really, no. The summoning line is arguably less powerful right at the end of the game (although Summon Grave Elemental is very worth it in big battles), but the start and middle of the game is where you win. Give me an air elemental/lightbringer/skeleton horde any day over rather expensive and not particularly powerful damage spells (which they are at the start of the game) . I started taking the damage path mainly because I found the summoning path too easy. Sure Blizzard etc. are powerful, but it takes a while to get -1 casting time and -40% casting cost and high damage. Ice elementals, air elementals, skeletons/ lightbringer are useful as soon as they're available, and if you use them to get loot and experience early in the game, in my experience you will win (I normally play on Ridiculous). Don't underestimate their ability to keep your Trained units alive as well by taking damage, which means more levels and more hitpoints for your Trained units; and when you're at full stack size summoning units tactically allows you to go beyond your max stack size, with all the associated Swarm etc. benefits.

Damage spells are fun and make a change from the way I normally play, but if or when I get round to playing my Insane game, I'll probably go with a summoner.

Hmm...I agree with you say as far as the early game is concerned, but I find them to become noticeably weak much sooner than end game.  It depends on your AI opponents, but as soon as they can train units with metal armor the Air Elemental is about the only one that can touch them.  That being said, I find the damage line much more useful by mid-game when damage spells start to get powerful--I'll take a mage with high spell mastery and all sorts of damage bonuses over a Grave Elemental. 

Certainly, part of making adjustments to the Summoning tree is to balance it from start to finish.  In my earlier suggestions, I was certainly not opposed to weakening the line at the beginning and buffing it later.  That's one of the problems I find with the tree--it pretty much stays the same from the start, the extra "levels" don't really make enough of a difference.  I'm not sure if you looked at my suggestions in my first post?  Did you like any of them?

Your post does bring up an issue with summoned units.  The fact that there are two ways to use them --1) as a unit summoned during a battle to essentially increase your army size until the end of the battle, when it disappears, and 2) as a permanent unit in your army when it is summoned outside of battle.  At the moment, there is little value for option 2 in the mid-game and later, which disappoints me, especially when compared to a "nuke" mage.

As for the discussion of the advantages of having a good early game and how it wins you the game, that brings the AI into the discussion and I think it could stand to use some tweaks for sure.  We all have games where we win it early, but there are always a few games, especially on harder levels, where at least one AI jumps ahead on points due to a good starting position.  Those are usually the most satisfying games, because the mid-late game is interesting. You are at a disadvantage against the AI's superior troops.  In those games I have found the Summoning Tree to be especially weak (except for the utility of the Grave Elemental) compared to damage, or even healing, spells at the point in the game where I am dealing with the AI's units. 

Incidentally if you're worried about summons not doing damage in the late game, although I wouldn't particularly recommend it because the Pyre of Man is so spectacularly useless, if you go down the fire route you can get Fire Elementals, which are quite powerful and will do fire damage, which will ignore armour.

Earth elementals do physical damage, which on top of how slow they are makes them pretty useless in the late game, except perhaps for tactically summoning a tank unit next to a powerful unit who you want to distract.

Well, maybe. Yes, the fact that the AI won't generally move its unit if an enemy unit is next to it is a weakness. And I agree the summons are acting as a distraction. But that distraction would stil be useful against a human, if not quite so much. The Zone of Control and Swarm bonus mean that Skeleton Horde (for example) would be effective against a human. Ignoring attacks which kill multiple skeletons, you're effectively forcing nine of the enemy to miss a turn. Lightbringer is only one unit, but it is hard to kill, and has a handy Blind ability as well. Even against a human it would be fairly easy to summon a couple of blocking units, assuming you already have a full stack, and they will give you extra Swarm capability as well as forcing the enemy to choose whether to attack your summoned unit or your trained unit.

An individual summons late in the game, with the exception of Summon Grave Elemental, is probably not going to win you a battle in the way that Blizzard might. But they're still useful. The way the game is designed (with abilities which you only get if you summon them tactically) pushes you to summon them tactically, especially late on. Having said that, I generally have an Air Elemental in my main army till very late; it's high movement, for a start, so it's not going to slow my main stack down, it should have high points, it has a useful special ability to knock prone, and it does high magic damage with spear special ability. It's a bit fragile due to lack of armour, but it's so high initiative I can generally keep it out of the way of trouble.

Otherwise I don't generally bother to keep summoned units permanently in my main army. Even with the Air Elemental, it will frequently be higher level (because of summoning bonuses my mage has picked up) if I dispel it and summon it again than if I try to keep it permanently to gain experience.

The game is designed that summons are fairly throwaway, often to be summoned tactically. I understand if you had a different vision of them, but you might want to look at mods (or design one yourself). If you want summons that will change the course of the battle, a good one to start on would the Pyre of Man. If he cost 100 mana and lasted five turns he might actually be worth summoning (and be capable of changing the course of a battle).