Well, the Occulus Rift comes with controllers, so while combat will probably be motion based, movement will probably be via joystick. Unless they release the NerveGear (wishful thinking). Looking around with the headgear on should still be fine.
Character customisation... I don't know if it'll let you go Neko, at least not in the early days, but there should still be a lot of options available. Not that everyone will exploit that since there'll be a mountain of dudes trying to mimic Kirito, or even more dudes trying to be Silica. There wouldn't be much point in that though, since your voice would still sound male (I'm about 98% sure in-game communications are done via built-in mics, so that'll make it difficult to pretend to be a girl).
Assuming combat is as I said at the top, it should be fairly simple. Might be a bit more like Wii games such as Red Steel, featuring a little bit of button pressing (namely for Sword Skills I should imagine). If I can find the article I read about motion-control in VR, I'll link it, but I'm sure that'll be a big part of it, especially for a game like this.
Given SAO's popularity, I think it's safe to say dedicated servers are guaranteed. It's a big game too, so lag is one thing they will absolutely be working hard to minimise, if not completely eradicate.
The Floors (in the show at least) were pretty big, but I don't think it'll take that long to go from town to town. Besides, there'll probably be horses you can ride, or else horse-like monsters that you can tame and then ride.
As for downloading... that could take a while, unless they decide to release a disc for the game (like WoW), which hopefully should take less time. Even so, Aincrad was a huge world, so it could take a few hours to install. I guess a part of it also depends on your PC's specs.
And now for my questions/thoughts:
1) Guilding and parties are basically a given, so I'm wondering if there'll be special Guild Halls for these guilds to use, or whether we'd have to acquire and develop our own.
2) The show featured Silica as a Beast Tamer, Lisbeth as a Blacksmith and Agil as an Item Merchant. I wonder if these job roles would be available as well? If so, I'd balance dungeon raiding with blacksmithing. I'd like to be able to forge my own custom weapons and armour, and repair it all as well. It'd also be handy to have a job system like that to earn extra money if exp grinding gets rough.
3) On the subject of custom weapons and armour: how much customisation would be available, and would it be something we have full control over, or would it be random?
4) PKing: another aspect of the show, but will it be allowed under the same rules? I'm not saying I *want* to be a red player, but let's face it: we've all wanted to kill a Kirito-wannabe. Just 30 seconds in the Rift is enough to make most people want to go on a killing spree.
5) Legendary weapons: They never appeared in SAO itself, but ALO had Excalibur, and Onigiri has those weapons as well. Will SAO: The Beginning have them, or could we forge our own interpretations of them instead? I've got designs for Durandal if the latter is the case.
That's all I have on my mind at the moment. I'll see what I can dig up as time goes on. Maybe some questions will be answered, maybe more will be raised. I'm definitely excited for this game though. I *would* say "I hope it's better than Onigiri", but that's not exactly setting the bar very high is it?