I've played HS. MTG, LOR. I just see that HS is better than LOR on simplicity, and to be honest that doesn't make it better to me.
I've put so many time on HS but to me it just become so boring not be able to interact with the other player turn at all.
That point (more or less it comes from MTG) is what makes me love the game. Also of course that you can have in a much faster way a collection to play competitive.
Also another thing to point out, the LOR app for Android it's the best by far.
In terms of competition/streaming: normally the people who watch the championships are casual players that should understand the rules of the game, so I don't see any problem to have a little bit more of complexity to the game.
Not gonna talk to much about MTG on digital, it's so sad that you need to pay to play some modes or to have a decent collection to be honest.
Just to finish, taking in account the lore and the graphic/animations I still go with LOR, HS have loose the opportunity to bring more lore to WOW world.
Sorry don't want to sound too unfriendly :3 that's just my opinion and of course everybody prefer more some things than others! Peace out!