I would not recommend putting the crusade on auto. The super easy difficulty setting is quite fine, and you don't end up missing out on some important quests or having stupidly damaging crusade outcomes. Plus, crusade management in WotR is sooooooo much better than kingdom management in Km.
I hate pre-buffing as a concept. Period. In all cRPGs including the old IE games. Just absolutely hate it. So the way I choose to play these games is to never pre-buff (other than in very rare situations where a specific pre-buff is mandatory to get through the encounter) and to just dive right into the combat, but offset this by lowering the difficulty level (in WotR I play custom difficulty with "moderately easy" enemies). I also only very rarely use offensive spellcasting and limit myself in combat to melee and missile weapons and support spellcasting. This is my standard cRPG playstyle, and perhaps why I so strongly prefer RTwP and not TB.
I used two mods to deal with those issues. First, a mod that allowed me to cheat in units for the Crusade mode, and then I just autobattled everything. I don't enjoy the crusade mode at all, and it's extremely tedious imo. It takes so long to do it properly. Second, an autobuff mod. I set all of the buffs I want (the mod has quite a lot of granularity as well) and one button casts all of them. It's so good.
Re. crusade army battles, right now the game makes it possible to auto-resolve them when your army strength is two or more greater than the enemy army's strength. So if your army is an 8 and the enemy a 6, you get that "let them flee" option when you make contact with them and you win absoluetly with zero losses. I have, without any mods, been able to easily recruit enough units into my armies such that I have two armies, with generals, that auto-win my army battles 90+% of the time. Only rarely have I had to actually fight, and even then with an army stronger than the enemy such that it was pretty easy to win.
