I would like to see a 2v2 team mode added where you can play with a friend (possibly 3v3 or more if they can make that work too).

I would also like to see some form of tournaments added, although, I'm not sure how they could keep the waiting time to a minimum between matches like they do for the current arena. I would like to see tournaments similar to mtgo has, but without the wait between each round, or maybe it would just be that if you enter this format you are ok with the wait time.

Daily tournaments like Warcraft 3 had would be awesome. In war3, you would have a 2.5 hour group stage where you can play up to 6 matches. It worked like arena does now where you get matched up with someone with a similar record and you can queue whenever you want. After the group stages the top 16 move onto the playoffs. I think all the rounds were bo1 until the finals which was bo3. The playoffs worked similar to when you challenge your friends in HS. You hit the play button and it says waiting for other player until they also click play. If they don't click play in a certain time they are DQ'ed and you move on. I think the whole tournament start to finish took around 5-6 hours.

Blitz mode

Although I read online somewhere that they are working on 2v2 mode for the next expansion. No idea what the validity of that statement is though.

A weekly giant single elimination tournament with ~2000 runners would be awesome. Say a 2pm EST start and would be done by 10pm-ish

64 and 16 man SNG's would be great as well. They would fill within minutes.

What I would really like is for the AI's to be actually good and to have them update decks. For example able to have the AI place face hunter well and being able to test decks against it would be great.

This is my qualm too. I get the AI is pretty terrible, but why not be able to custom make their decks? Or be able to pick your own decks for them to use, at a minimum