so by now i recon everyone has shitton of alts and switches between them pretty often. but the problem is, that you need to exit game, pick your character, getting back to the game and start playing. imo this is lame way to play alts, and it would be avoidable.
what about this:
you enter the fight, pick a character and then equipment. multiplier doesnt reset since its still you playing for these character and you merely switch class.
this would also allow to limit the number of class specific troops like infantry, ranged and cavalry...