I tried to spend a good chunk of my weekend playing in the online arena of Hearthstone to get a sense of how that worked but was only partially successful.
Since the game will occasionally give you different quests to fulfill in order to earn gold for packs, I ended up going back to the practice arena to play the AI and earn enough basic cards so I could play against people online and not be horribly outmatched. This is a good way to encourage players to understand the different strategic strengths of each character but it's a drag if, after putting all my time into Mage and Warrior characters, I suddenly have to fulfill a quest using a Priest. There are enough generic quests that this probably isn't an issue for most people, and it's only my quirk of OCD that pushes such tasks on me but that doesn't subtract from the drag that it represents.
The online game plays a great deal like the AI one: one where attrition against creatures is the surest path to victory, so the more removal or creatures that tie into removal you have then the better off you are. Drawing cards is good, so anything that does that is good. I have had the wonderful surprise of having players lay down cards that I didn't know existed, such as the 12/12 beast that destroyed all other creatures in play. That was very, very bad for me but I had removal so I killed it on my turn and lay down the creature I'd been holding back. Still, the sense of being surprised was a good one and not horribly losing because of it felt fair.
Another game had me playing from behind the whole time and I lost. As with many collectable games, the person who has the bigger collection has an advantage over the newer player and it was very clear that I was up against someone who had paid their dues.
There were some neat online only quirks though: my opponent played an effect that allowed them to copy a card from my hand--but I had no idea which one they got. There was also a creature that gave us both spells to put in our hand and these kinds of effects just cannot be reproduced in a real world TCG without some serious consequences.These tricks suggest that they really have put some effort into making their game work.
As a short, kind of throwaway game, I get Hearthstone. The ability to change characters helps broaden the options and change things up without giving the game too much depth-something positive or negative, depending on how you feel about that. I'm certainly pleased that they are trying to engage in mechanics that are media-specific; if all they did was replicate what a regular card game would do then there's a legitimate "What's the point?" question to be asked.
Still, at the moment Hearthstone feels a bit like a 'burner game', like Peggle, Plants vs Zombies or Bejeweled, where I'll play the hell out of it for a week and then not touch it for a year. Perhaps when it moves out of Beta and there are more players it will feel different and if I can get it on my iPad, I certainly will. It's a solid game, I just don't know that it's a great one, yet.