I'm not too worried about multiplayer. I doubt it'll be anything more than an option, and it's an option that I won't use. Soon enough, I'll get to see how optional the "bridge the gap" DLC really is. That's what I worry about. Honestly, I didn't even notice the multiplayer announcement on that page.
[spoilers?] What I read about the plot looks awesome. Building an army like in DAO and visiting Earth were two of the most expected things for ME3, at least from what I've seen on the forums. Can't wait to see Earthborn Shepard's reaction to seeing his/her home planet, probably in flames. I know I have two who would be angry about it and hate the Collectors even more, one who couldn't care less because he already escaped from Earth years ago, and one who would just joke about if he's even allowed back on Earth after his past. I also hope we get to see Palaven when we're gathering the alien forces, and Garrus' family. I'm sure my FemShep who romanced him and encouraged his Renegade tendencies wouldn't go over well with his father.
But one of the most important things on my list for ME3 is for Shepard to have a great "I told you so" line to the Council, hopefully something that involves the words "Ah yes, 'Reapers.'" If they really do try to blame Shepard... I can see a lot of my Shepards wishing that they had let Sovereign kill the Council way back in ME1. It would go along with the idea that the Council will/try to arrest Shepard though, and I've always liked that idea.
[/possible spoilers]@Sir Ulrich: Motoko sounds interesting.

I like that "when you want a problem shot, ask a turian" line too. It seems very true about the turians we've seen so far. My MainShep hates batarians too (she's a Colonist), but she does like most alien species. Except the asari, because their flirting annoys her. Turians are definitely the highest on her list, above other humans.
@Sable: I hope ME3 isn't like the seventh Harry Potter book was for me... excitement and worry before the release date, confirmation of worries, disappointment, and death of favorite characters (again). xD Shepard should start working on that biotic barrier all of my favorites need to hide behind for plot protection.
@IndelibleJester: ME1's multiple endings were based on the Council - alive, dead, Anderson or Udina for councillor. Even though that choice hasn't made much difference yet aside from air-quotes and the reaction of that turian store owner on the Citadel, it's still there.