As Zerkovich has said, most veteran players (myself included) settle at normal or Hard Battle difficulty even if they have the 'skill' to beat legendary, because the higher difficulty modifiers ruin the game balance and ultimately do not actually make the game harder, it just makes you use more elite Ranged/Single Entity Doomstacks.
Will Warhammer III have a reworked difficulty system? I certainly hope it does, it sorely needs it.
I'm not asking for magical AI improvements, but CA should change the way the AI is buffed.
A quick TL:DR of what Difficulty does:
1. On Harder Battle Difficulties, the AI gets:
2. +10 Morale, which is enough to bump most units up a Tier alone
3. 15% to all 3 melee stats: Attack, Defense, and Damage, which all adds up to a very dangerous buff package.
This compounds also with Free Veterancy from Camapign Difficulty, which turns AI melee units into absolute monsters (except against ranged units, artillery, and spells).
1. On Harder Campaign Difficulties, they also get:
2. free Veterancy per turn, which further ups their melee stats (Triple Gold Chevron legendary melee units will basically wreck player infantry no matter what)
3. high replenishment, which helps their infantry trade even better,
4. player replenishment is lowered on high campaign difficulty, making melee units even less viable due to harder casualty replacement.
5. Player upkeep is massively nerfed per army (+15% upkeep per Lord), hard-incentivising Elite Player armies that must be able to win without taking casualties against the AI horde of Hyper-Elite Melee infantry.
All of these compound together and create an environment where the only reasonable option is to ignore infantry entirely and use other units, such as Ranged Units, certain Cavalry (basically just Brettonian Cav), and Singe Entity Units (monsters and Heroes), and use Lightning strike to kill multiple stacks a turn in a series of samey Ranged-Spam battles.
TL:DR CA pls fix the difficulty settings.