>>25326748>>25326753It was 11 minutes, 7 of which was a recap of the series to date when it wasn't even the 20th anniversary.
The trailer itself was 1½ minutes and the last 2½ minutes was basically a recap/outro.
Keep in mind that the blurb about this one says that they'll be celebrating the 20th anniversary, an doesn't even mention news, which leads me to suspect that more time will be spent on a retrospective like the 7-minute one from the X and Y announcement or summarizing where the series is right now (Go, shuffle, Detective Pikachu, XY/ORAS, etc.) than announcing a new game. That doesn't exactly leave very much time for the new game trailer, and even less time for an explanation of it.
Expect a very brief teaser or less.