I personally don’t see much a need to switch classes. For me, ’Sin works out great. But then again, half my cards are geared towards ’Sins, so I may just be lucky.
If you picked a sin or pyro, it’s probably a good idea to unlock the other at some point down the road. Pyros are especially nice for brawls since they’re able to do some actual damage while tormenting or using heals, if they get a crit.
well in some cases you don’t want to do damage with your torments (if the opponent has soul stealers for example)
I started off as a Pyro and unlocked sentinel next.
I also think Sentinel is the most versatile class at the moment.
However sometimes you just et cards that have interesting effects for different classes.
Queen lena for instance is probably best on Pyro’s (Druid just isn’t worth it: as pointed out here)
Planned assault can work very well against high defense Brawl bosses if you play an assasin.
If you want to get rid of acid Flasks or Soul stealers with spear of destruction assasin is also a good choice but Sentinel works fine as well.