Hearthpwn

Adapt is a very small mechanic and can barely even be counted as one, adding any more of adapt cards would be immediatly overusing it. If anything a similar concept to adapt will come where you can pick from completely different things.

Quest on the other hand are a whole new and unique mechanic that was overall really successful, and there's a good chance they will be revisited once a year or when our current quests rotate out. They almost definitely won't come next expansion as it would not only wear out quests too much but would also restrict them from coming up with other cool ideas.