I actually managed to get a bonus from the roll-back! Attacked in crypt, switched accounts then came back & could reuse my hero but the team I attacked were still dead. Don't get me wrong, this bug is ruining my enjoyment of the game completely, but I figure they're more likely to address it if it's helping us. This doesn't even begin to make up for all the things I've lost because of it though.
Edit: it was only one hero I could reuse, removed plurals. Can someone more tech savvy than me work out a way to turn this into a hack so you get to reuse crypt heroes over and over? I'm sure that will encourage them to fix it.