not really, but only generals with nightfighter traits can participate. you don´t get this massive battles, that get ctd when reloading into the campaignmap again. for example in this situation from above:
figthing nightbattles, you can pick them off one by one. every of the 4 thsd unit stack can get massacre battle per battle + step by step. if only one general has the nightfighter ability, switch armies, if they get to depleted. this way i slowly grinded the horde into the ground. some citiysieges can also help to thin then out.
i set AA of and use my nvidia AA outside the game
grass on medium is more important (there´s more grass than trees)
Unitdetails only come to play at close distance.