I guess I'll throw in my two cents since I've been watching this play back and forth. Be prepared for tl;dr.
The first game made it clear that the fight with the reapers was NOT going to be easy. It took a lot of sacrifice and power to kill one, and imagining an entire fleet of them... I just couldn't process it. Part of me still believes it's a fruitless endeavor and Shepard and earth and everyone are all gonna be destroyed and everything's going to be for naught. There's absolutely no possible way there's going to be a happy ending to this series. There never was. The entire point of it, even as stated by Femshep in the trailer, is survival at its basest. Nothing else.
I always imagined Shepard pulling a heroic sacrifice to save everyone. That's, at least, the Shepard I played through the games with and imagine. Him/her dying is acceptable to me, because of the situation, and I'm surprised there's an ending where he/she lives at all. Since Earth is revealed to be ground zero for the reaper invasion, I don't imagine it lasting long. If I can somehow save it with a large enough fleet of my own, great. But being attacked so quickly by that much firepower and planning doesn't leave much to the imagination.
As to the Normandy crashing, I'm thrilled they survive at all. I thought they would be blasted to bits in the gunfire or go down with Shepard. I don't care if they're stranded, all that matters to me is that they're alive. From the grandpa/grandson video that was released, they were able to live on peacefully and have families. Considering they were just about to be violently wiped out by a race of sentient machines, I'd say that's an improvement. The details aren't clear about the specific companions, such as Tali or Garrus, so I'll simply have to wait for the release.
There are things Bioware does that I like, and there are things they do that I can't stand. I'm not about to forsake a series and cut off a pre-order because it may not end quite how I wanted it to. I wanted a lot of things that I didn't get just like in any other thing ever, just like everyone else, but I'm excited about the final release of my favorite series and I'm going to play the crap out of it. I love my Shep and I won't leave her hanging like that.