Well, ITT: lots of people ignoring the core point of the OP.
I’d go to say that Duelyst is one of the most “balanced” (whatever that actually means) games I’ve ever played. If you think Duelyst has an issue with power creep / OP something, you should really try playing a larger variety of games. I think the devs here have a good balancing philosophy and have a good idea of where they want to go with a lot of cards / archetypes in terms of design (Vetruvian being the outlier). The only card in the new set that I think could potentially be power creep is Punish, but we’ll see.
Anyways, all of that is not to say that CPG will release a perfect expansion, but just that they have a decent history (speaking comparatively to other games) and have typically solved problems with unhealthy cards. Frankly, speculating on whether or not the sky will fall with the new expansion is pointless. Will there be some cards that need balancing? Probably, again, no developers are perfect. Will Duelyst crash and burn? Probably not, this game has a good future ahead of it.
Calm your nerves, get a nice comfortable chair, a cup of hot cocoa, and sip peacefully until Thursday. Duelyst will be fine people. If it’s not, you can make all the nerf threads you want after you’ve tried the cards yourself (preferably for more than a few days, but we all know that’s not happening).
edit: P.S. A little bird told me this- since the expansion is already coming out tomorrow, worrying about the balancing will do absolutely nothing because it’s far too late to change any of the cards. Huh.