So, I've now given Hearthstone a try, it's been on my system for a month, I've opened up all the heros, and played a few online matches, and to be completely honest it got old and tedious very quickly. Just my experience, only my opinion, but it's not even close to the strategic quality, gameplay variation, and replay value of M:TG. Without the online component it holds no interest beyond a few hours play for me, and even with it, nah.This is slightly off-topic, but yes there is an RPG element (although very basic) to the game.
You basically level up your hero and earn gold to buy new cards.
But I'd recommend you to give it a shot, it's a free game and it's a lot of fun, in a very tactical way.