While I can see where you're coming from there, the fact that they showed a teaser for it at the 10th Anniversary and nothing at TGS still feels a bit off to me. If it weren't for that, then I'd probably be less skeptical of this.
I mentioned in a previous post that the teaser at the 10th was likely just a treat to those that came to the concert. It really didn't show much either. (Maybe, they weren't ready to show a long teaser?)
animagic4u actually did come to the 10th anniversary and pretty much said the same thing.
I can't explain it, but it felt like they were rewarding us for being there even though it was such a short tease.
Besides, a lot things probably contributed to the delay in Namco giving us real info/trailer on PS4 im@s such as the VA's busy with family, maybe giving CG some time to shine, other projects, etc.