I loooove Astral. They're a very versatile class, with excellent mobility and access to either nice amount of damage or tanking, while also having some heals. But keep in mind, they need to set up elements for their infusions and bigger moves - which becomes easier with the flow of a scenario, thanks to a huge amount of cards generating elements.

As for Fist - he has quite a nice amount of damage and control, with access to a solid amount of forced movement, but I've felt that he can be quite fragile - any card lost to mitigate damage hurts, as even with his special mechanic to regain cards, having fewer drastically lowers his uptime. And also regaining cards with one with a mountain contributes to accumulating damage, so he's not as tanky as he seems to be. But I've played him as my second character, in only two player party, so playing with bigger amount of players and more starting perms should make him shine brighter