Well, what can I say that hasn't been said yet. I woke up at 6:00 today and quickly checked NeoGAF, Twitter and then some pics of the trailer, but until five hours later I couldn't get to it. And man, what a blast with the trailer.
I loved everything, if they get to capture that artwork's mood for the game, I'll be sold (and if it turns out to be a good game, sure xD). I hope they are more upfront with more frequent updates (I think they have big ones next weeks), but yeah, they said the same a year ago. But that demo so "soon" gives hope that they're on the right track.
About Stella, yeah, her best design by far is 2009's. BUT, her design now is gorgeus, she's really, really beautiful. Actually, scracth that, I think it's my favourite design of her, although I guess she won't always have that hairstyle.
Regarding Noctis and Prompto's new designs, I liked them both, especially Noctis. Prompto looks more charismatic, and Noctis is basically the same, but small tweaks and much more detail give him a more masculine appareance, which I really welcome.
BTW, it'd be really shitty if they change Stella's name, but I don't think they will. The next logical guess would be that maybe that's the black-haired woman's name (the trailer scenes and voiceover doesn't necessarily have to match) and perhaps she's Noctis' fianceé or something (since he's a prince). Or maybe Luna is another different character lol.
So, really happy about this! Really looking forward to more info, hope it hits soon.