To be honest, that one tweet everyone was referring to (even many game news sites) wasn't at all what got me hyped for a possible DOA6 announcement. I was already wondering why so many saw it and thought it was that big of a deal.
I was hyped and pretty sure of a looming DOA6 reveal, because of the much longer ongoing talk of there being something at NEC, already a year ago. Also the fact that DOA5 is an old game by now and that they finally stopped with the DLC madness. I'd also still argue that sitting out this generation and leaving the spoils alone to Bandai Namco's Tekken and Soul Calibur, especially after Virtua Fighter is dead too, is a huge oversight and a big mistake business-wise. But what do I know, I may have studied marketing, but I'm no fighting game developer or video game marketing specialist. Koei Tecmo probably knows what they are doing. I hope so...
Team Ninja actually didn't really do anything misleading here. I wonder if they noticed all the hype for DOA6 in the last several days and were like: "WTF is going on? Why are they so sure of DOA6? Do they know more than we do? This probably won't go so well...D:"
Poor guys, they were probably really nervous of the fans' reactions after the tournament. Maybe not the higher ups of Team Ninja and KT but the little guys who keep everything running and directly engange with the fans.