Bit disappointed that the first DLC is only multiplayer stuff; I've absolutely no interest in that side of things, however much EA try to give it the hard sell. I'm really wondering if they're deliberately trying to alienate as many people as possible...

I can't help but think, though...
Just imagine the reaction that releasing any sort of single-player DLC before the Extended Cut DLC would cause. (If Bioware's forums are anything like this one; releasing - or even discussing working on - DLC before what the fans have prioritized generally... doesn't go down so well.)
Myself, I'm cautiously optimistic (or perhaps more aptly - pessimistically cautious) about the Extended Cut. Personally, I'm... "okay" with the ending as it stands. I just wanted some more closure and some loose ends tied up.
The problem I see with any sort of additional work on the ending, though - what got released, how things tied up in ME3 as it stands now: that already was Bioware's (ostensibly) best attempt at an ending. Maybe they had some time issues, maybe they rushed it a bit. But I don't doubt they felt they already did the best they could.
So (in my mind) whatever comes out in this Extended Cut DLC - I can't say I ever really saw much chance for some magical new inspiration to come from the team, that would give us all an ending beyond our wildest dreams. Yeah, yeah - other works have re-releases, Director's Cuts, alternate endings, etc. But in all of those cases - what you end up with is something that's simply different. Not necessarily (and certainly not by any objective criticism) "better."
The ending is what it was (and I'm not a fan of it, certainly.) But if they didn't put out Shakespeare on their first pass? It's not like we're getting Homer's Odyssey the second time out.