The problem with designing cards to do something other than damage, is that increasing damage output will always be king and the card which gives the most DPS, will be selected every time. Make all the cards not buff DMG and do a different effect? You'll still find little use for most of them, as current healer toolkits are bloated beyond belief and a card which gives damage reduction, will just be overshadowed by exaltation or celetial intersection anyway, for example.

Conceptually giving cards different effects is interesting, and maybe it can be done well. But looking back at SB, I think the best state of cards is if they're all the same (i.e balance). Is it interesting? No, but in practice and gameplay you're always using them. I'd rather have buttons which are less interesting, but find use every time, than interesting buttons which are never pulled out or see the time of day.