I wouldn't worry, it still seems like there is stuff they are holding back.
They definitely have not announced the entire roster, they haven't announced any DLC...
It's similar to the strategy they use with the NBA games, based on that we should be at least seeing a trailer soon.
But based on the character select screen we've seen, there is room for at least another 20 wrestlers to be announced.
Really hope to see 2K do something with characters being updated throughout the year via some form of roster updates. They do it with the basketball game so it can't be that difficult. But people like Ambrose, Rollins, etc. should absolutely be updated with their new gear.
If they went with DLC every month with like 4-5 new characters or some mix of legend/nxt/wwe/diva/wcw wrestlers, that shyt would sell. I don't see why they aren't more aggressive like that.