True enough, I'd hope that we get somewhat 'lengthy' trailers for II.5 and III at Tokyo Game Show, while D23 just gives more information, promotional media, and perhaps a few surprises. Sora's new outfit, perhaps?
We'll probably get a 2.5 trailer for sure. Not so sure about 3. And Sora's outfit seems like the most likely thing that would be unveiled next as far as anything "visual" is concerned.