Auto-resolve odds should not be tied to battle difficulty

This was never a good idea on principle, but the current state of the battle AI has completely undermined any positive aspects it might have had.

Prior to the slider separation, the problem was as such:

 

* If you wanted to be able to auto-resolve trivial battles and move on, but also wanted the battles you did play to be more challenging, you were out of luck. Playing on Hard/Very Hard with factions that fare poorly in auto-resolve and/or have low replenishment (looking at you Tzeentch) meant you had to even play out battles that you could dominate while AFK. * If you liked playing battles, but didn't want balance to be thrown off by stat bonuses, Normal battle difficulty would entice you with Decisive Victories in nearly every situation (to say nothing of Easy). *"Well, I could take this fight with Wood Elves, but does that really sound fun?", "I could fight Vlad, but...", "These skaven are just going to run away at half health, why not wipe them out?", etc.*

 

The stat slider introduced in 4.0 might have at least solved the second issue, if not for one glaring flaw: **the battle difficulty setting, even more so than before, doesn't actually correlate with how difficult battles are**.

 

Currently, rather than engaging the player's army, the AI is trying to do far too much on the battlefield - especially in regards to countering the player's actions. The higher the difficulty the more they *try* to do. The end result is that the AI on higher difficulties ends up performing far worse (and is far more predictable/exploitable) than on lower difficulties in any situation outside of a giant melee brawl.

For example, on VH, it is extremely easy to **accidentally** get the AI to get stuck endlessly trying to reform lines, meet up with reinforcements, protect its flanks from enemy skirmishing units, and dodge spells/artillery, all while its army gets picked apart piecemeal. It's so easy to do that all it takes is something simple like trying to kill their artillery with a lord/hero, or skirmishing with even a single ranged cavalry unit.

 

So, now we're stuck in a situation where, if you want an AI that offers more of a challenge - and most importantly, one that breaks far less often - you need to play on lower battle difficulty. But this means that you're stuck with an auto-resolve bias that heavily favors your side, meaning that you have to force yourself to fight almost every single battle lest the entire campaign become incredibly easy.

Add in the fact auto-resolve is currently in an unbalanced state in the first place, and it makes for a very poor experience overall.