You had many horses left because you were doing well and your empire was controlling several sites.

I finished 2 games on normal on 0.87 and at start, when I had around 3-4 towns and really needed the mounts I didn't have as many as I'd liked to (and maybe that's a good thing).

Another resource I lacked a lot was crystals, I kind of lacked crystals whole game even in the end game when I was the largest empire.

To overcome the lack of resources I had to do something fun: trade with the other factions. In the end I suspect the AI was more hurt by the lack of resources than I was.

Another thing I feel I have to repeat: it's fine to balance mounts by cost or by availability as long as 2 things are kept in mind: 

all mounts should be useful, desirable upgrades.

balance the mounts against the other upgrade slots (capes, boots, etc) not against infantry ( troops not using this upgrade slot)

If I were Stardock, I would have pools going to see, once a change is made in the game based on forums feedback, how many people complain about the change. 

Honestly. "HORSES ARE TOO NERFED THEY ARE USELESS NOW." Ugh.

Wargs still give +2 initiative, that bonus alone is huge. 2 extra move on horses is worth it, with first turn combat bonuses to boot.

Right now, I think the mount dynamic is very good. Wages seem to be 30% higher for mounted units, and the supply of horses/wargs is limited enough that building infantry makes strategic sense. IF YOU CAN AFFORD IT, you can make 100% mounted troops, but in many games hard choices will be required. 

Functional.  

The bottom line for this game is for it to make a profit.  If newbies find it too tedious, it will not sell.

Oh, please! 

If you don't want to think while playing a strategy game then maybe you need to go back to playing Donkey Kong.

Haha indeed:

"Am playing one of the best 4x games on market, but to win I just press auto-resolve every time and move stuff around on map where to go next. So yes, the game is INSANELY hard (it says so in difficulty settings), but I'm very skilled with auto-resolve, I click it faster than AI can react, and I win".

Go to CoreImprovements.XML (it's in data\English\Core Improvements), search for the Stable (make sure it's the one that produces horses; you should a set of GameModifier tags that include a reference to horses), and make two copies of it in a new text file. Add

<UpgradesToImprovement>BetterStable</UpgradesToImprovement><UpgradeTier>1</UpgradeTier>

to one of the Stable entries, and change the internal name of the other Stable entry to BetterStable (you can pick any name you want, I'm just using this as an example name). This should then look like

-<ImprovementType InternalName="BetterStable">

instead of

-<ImprovementType InternalName="Stable">

Then find the portion of the XML for the BetterStable that says

and change the part that says <Value>0.2</Value> to reflect the production rate you wanted (e.g. 0.5, if you want one horse per two turns). You might also want to change the <Provides>...</Provides> text to reflect your changes. You should probably also add <UpgradeTier>2</UpgradeTier> to the BetterStable entry; the <UpgradesToImprovement> and <UpgradeTier> tags are found right after the <PreferredTerrain> tag in the Air Shrine entry, so you might put them at roughly that point in the Stable/BetterStable entries. Save this file in your LegendaryHeroes\Mods directory (which should be in My Documents\My Games, if you used the default install path), enable mods in game, restart the game to allow the changes to take effect, and you should have your enhanced stable available for use in game.

Another thing you might try is to see if you can change stables over to provide only X horses total (by changing <PerTurn>1</PerTurn> to <PerTurn>0</PerTurn>), although you'd then need to make your mounts increase unit wages by one horse per figure per turn (or some fraction of a horse per turn, if you wanted). This way, you could use the available horse resources as a cap on the number of mounted units you could field rather than having the ability to support a theoretically infinite number of mounted units off of a single stable, given sufficient time to produce mounts. Improvements to the Stable and adding additional Stables would then be the means by which your mounted army could be increased. However, it would probably take a bit of experimentation before you found a number of mounts per stable (or improvement thereof) which you were satisfied with, and I personally don't know how to add horses as wages to a mounted unit.

I'd suggest that if you wanted to do either of these things and ran into trouble with it, you should ask over in the Modding Help thread in the LH Modding subforum.

For the same reason as why your champion has to buy all his armor and weapons for a cost that could rush out two or three units of troops equipped with the same kind of stuff. Apparently the weaponsmiths, armorsmiths, and horse traders are willing to give stuff to your armies for free (or at least only require the materials to produce them), but want a small fortune when equipping champions.