For me personally, MoP has been a monumental disappointment. I played for one patch cycle, 5.2, and have been unsubbed the rest of the expansion. While I am pretty sure I am up for disappointment again, I really hope Blizzard can pull me back into the game. So I will put a list of what I am hoping they will implement to draw me back into the game. Then I can compare it to the Blizzcon reveal at the end of the week and see how far off I was.
Deemphasize dailies and LFR: I don't want to be rid of them, they serve their place and lots of people like them. But I do feel there are too many paths of power and progression tied to both and make them overly important than what they should be.
Bring back 5 mans: There needs to be a bigger emphasis on making 5 mans a form of end game in their own right. I feel that a lot of people would prefer getting LFR quality loot in time by doing activities they like. I want drops to matter in 5 mans and not be completely irrelevant for anything other than bringing up your ilvl to queue for LFR. Give 5 mans variety and give us a chance to eventually get LFR quality gear. Yes, yes, LFR should get it much faster and more reliably, but given time I would like to earn them enjoying the game in my own fashion. Like back in WotLK days when Badge of Frost were obtainable in 5 mans. You could get baseline raiding gear given time if you did enough 5 mans, but actually raiding gave you better gear faster. I see no problem with this.
Scenarios should tell stories, not be part of progression: They were designed to be like group quests, yet heroic scenarios gave a chance at better gear than 5 mans. This makes no sense to me. It often required less teamwork, for regulars, and the items were very random. I feel they should tie into zone questing and deliver solid stories, but they shouldn't offer rewards greater than 5 mans.
Get rid of currency caps: No one likes them. I don't care how it's balanced. I don't care how you choose to limit the rewards or increase costs. Just don't tell me that I have gotten all the currency I can and I have to wait to get more. It's not fun.
New player models: I just want my female taurens to not look like models from the RTS just scaled up in size. I love them so much, but they are painful to look at. Give them as much love as you do to the pretty females and stop playing favorites.
No new classes or races: Balance current classes and fix button bloat before adding on another class. Flesh out and finish lore and stories for the current races before you add more.
4 specializations per class: While this might counteract my previous point a little bit, I feel it would be a much welcome addition to the game. Some of the button bloat could be pushed into the new specs. Weapon and armor imbalances, like spell plate, could be fixed by doing this.