So, you want a way get even stronger, even faster

So, you could use all the high end skills and spells, next I assume would be a request to make cities generate more mana

Ohh my, poor AI is in trouble, as if it weren't already!

The only way this is acceptable is if AI gains XP faster.

And then you will get more XP for defeating higher level opponents.

I suggest there would be an option when creating a new game to let AI gain XP twice as fast.

Quest exp and armies exp hilariously low. I defeated sovereign and killed legendary armies but cave bear gave me more exp.. probably because that was legendary cave bear.

Game is already steamrolling when we kill creeps or beat sovereings. determine who win game is often who won early game and got more creeps. unless someone make serious mistake in battle or tech.

To be honest it feels like a step back how it is now. I have fond memories of late FE having high level Sov's after a tough game who where quiet potent. In FE:LH i'm just getting more and more annoyed. The game is great fun, but leveling is pathetically slow. Plowing through 3 deadly armies that could potentially cripple my main stack is worth almost nothing. 

 There has to be a better middle ground. The values as they are just seem way way to low compared to the world.  

I dont enjoy killing AI armies and getting nothing for it either...especially when that stops me from killing monsters so I can actually flipping level up.

If the AI exp HAS to be so low to balance the game...maybe the AI should stop sending so many fodder units my way and send more substantial ones.

The constant stream of fodder units only serves to make me put my main army in "swat the annoying stream of obviously fail armies coming my way for no gain" mode, until I can get a 2ndary army to take over so my main one can level and do a few quests.

Fame seems more appropriate than extra XP, which can remain sort of tied to threat level.

AI champions and sovereigns aren't necessarily that dangerous, anyway, especially once they've been injured a few times or the sovereign's been defeated a couple of times and his side's mana pool has been drastically cut.  Giving an automatic XP bonus just for their presence would make farming enemy champions viable because they can't actually die unless the AI decides they've finally been crippled into uselessness and uses Steal Spirit on them, and I don't know that the AI ever does.

Not too impressed by AI-controlled city garrisons.  The city troops are not terribly experienced, aren't pre-buffed with Nature's Cloak or Evasion or whatever (not even existing until the battle), tend to have iffy magic resistance (a dragon can solo cities often, just from fear giving such an edge; confusion, contagion + curse, Mass Curse, Pandemonium, Titan's Breath, other nasty approaches abound against troops with unremarkable magic resistance, which they'll probably have unless there's a magic-resistance-path Defender in town), guardian wind greatly hampers arrow fire (and there's no way for a defending mage champion to dispel such an enchantment, either)... I had an champion-heavy numerically small but heavily enchanted army with ~150 attack/120 defense (total)  and no summoning magic utterly destroy Yithil garrisons with 700+ attack because the garrisons couldn't deal well with the chokes on city maps and they couldn't bring all their melee weapons to bear at once, nor were they prepared to deal with the odd fireball.  

I'm not convinced. This is clearly a matter of taste, but personally I think the balance is fine (although possibly there could be more of a bonus for killing enemy heroes). Currently in my games there's at least some mix between killing an AI, going on quests, building up my kingdom before attacking another AI, deciding whether I want to kill the last AI, do the quest or do the Spell of Making, etc.

If you get lots of XP for killing the first AI, then the quests and building your kingdom parts become more or less optional. The way this is implemented with very low XP for killing AIs is not very subtle, perhaps a better way could be found, but I don't mind particularly as long as it makes the game more fun. And personally I think the fact that the current system promotes a more mixed strategy does make it more fun.

At first I was surprised that you didn't get the AI Sov's magic items (as you do in HoMM). This would probably be unbalancing, but I agree with more Xp or perhaps one random item from the AI. If the game doesn't track AI magic items (for some reason) then it can be just a created random item.

Interesting idea. Though, the AI would have to be somewhat sensible in the utilization of items. None of that 50 bracers stuff that happens.