Let's clarify something up, ok.
What Nomura actually means is a matter of context. It depends mainly on what he means by current. Current could mean as in the current Timeline in which they wear their KH2 attire. However, he could also mean current as in what has been seen of 3D thus far, which would mean that they would start out with their KH1 attire, that is also the only thing we have seen thus far. Therefore, his sentence can be interpreted as either.
On the Armor, well, Mickey found his way out to other Worlds with the Gummiship and in BBS he Travels with Yen Sids Star-thingy, then later using the Hallway of darkness Portal-thingies. There he wears his Robe. But why wouldn't he use the Armor? Well, I believe it's safe to assume that he was in the RoD for awhile and Armor, unlike a Cloak, is effing heavy. Yen Sid is no argument at all, as far as I can recall we've thus far only actually seen him sitting in his Tower, no reason for him to wear Armor there. Even if Characters other then TAV use Armor, you wouldn't necessarily know it. We do know however that Eraquas and Xehanort also had Armor, so seeing as the majority of trained Keyblade Wielders use or used Armor, I believe it's safe to assume that it could very well be a actual Master thing. (Besides keep in Mind what Mickey might have looked like with Armor, Disney doesn't want their Characters presented in the wrong light.) So, besides Donald and Goofy there isn't anything speaking against Armor and Gliders. So, we take a quick look at some of the newer Title, BBS and 3D, mainly BBS. We are alone at nearly all times. In 3D we have thus far also not seen anything about companions following us around. So it could be that we are being weened on the idea of playing alone in the future. It is also possible that Sora would want to go without Donald and Goofy, afterall, they are his Friends and they don't really have a affiliation to what is going on, so why would he want to put them in harms way for no reason? Of course it wouldn't be very Donald and Goofy to just shrug that off, I could see them following him on his Glider with the Gummi Ship, him eventually just going back on board the Ship, still however being very capable of using a Glider and Armor. Also, this seems to be the only obvious means of Transportation open to Riku, so he would probably get the Armor and what not. Why give it to him and not Sora other then Gameplay reasons that would create a kind of Plothole. Some could argue that Riku might be the only to pass, seriously, I doubt that, if anything I would expect it to happen the other way around, but even then, Terra and Ventus weren't Masters, yet they both still had Armor and Gliders. At this point I would like to state that with Master thing I meant actually being trained. Riku and Sora just kind of stumbled into the whole story.
About 3D in itself. I don't have anything to back it, but I think it is going to be a Simulation, not an actual Dream. I believe Sora and Riku will very well be aware that what is happening isn't necessarily real. This would also explain the random Character Switches, it could simply be Yen Sid changing which person he is focusing on at the moment. It could be that they have to relive certain events, basically a test if they could repeat the success they had in the past or if they really only managed because of all the people working in the background. For me the only real question would be if they would retain any knowledge of the past or even the idea that it is a simulation while actually inside it, that wuld be a way to explain the KH 1 Clothes. It is also the only way I could see Riku actually having some kind of struggle with the darkness again.
Also, concerning new Clothes altogether. People saying it won't make sense because of the timeline should pipe down. All we know thus far is that Sora recieved the Letter shortly after coded, nothing more and nothing less. We have no clue what kind of Time Span 3D will cover. We don't know how long it would actually take for Xenahort to reform, so basically we have no idea how pressing the matter actually is at the time. Especially with ideas of Time Travel somehow being (although I doubt that seeing as how Xehanorts actions in BBS would make little sense if he could just travel through time, or anything else he does for that matter) given. So, basically, anything could still happen that passes a year, I don't see that being a Problem. So, new Clothes for 3D or KH3 ARE definitely possible.
