From what I remember there was never any specific development for Vista (aka code names, etc).
I think you're correct. Once they killed longhorn, the rehashed XP kernel was just called vista. I think they tried to keep the longhorn name around for marketing's sake, but it wasn't that project anymore. They tried running the new stuff on top of it, but it just kept crashing. So, they removed the features one by one until they were all gone and nothing but aero ran (which still performs poorly, stardock does better than them).
Expect nothing good from the new OS. M$' track history will prove itself, once again. Any useful or "new" features will most likely be overshadowed and rendered useless by its bugs and inefficiencies.
And for the record, Vista RUNS LIKE SHIT! XP on 512 is about equal to vista with 2GB. I've used it many times on many systems and it's the same result, every time. I'm twiddling my thumbs while running apps and then I masturbate if I have to copy/move/delete files (and that's on systems that I clean up or install myself which practically doubles the speed, XP x64 FTMFW).
Sure, sure, it does work fine for email, browsing and MP3s (but then so does 2k/XP so why downgrade to vista). I installed it on my buddies comp that I built (2GB ram) and just for that stuff, it runs fine. But for any serious apps (lol), you know, something that is taxing or running multiple things, it's worthless.