Sadly from the wording of it it seems like Illfonic are going to be using the same "it's totally random whether or not you get to play as the Predator" system that they had with choosing who got to be Jason in F13. That's a bit disappointing if that's the case. Dead by Daylight has proven that it's perfectly capable to have a game like this work while still giving players the choice as to which role they want to play.
Problem with that is everyone will likely want to play the Predator.
No doubt that's their reasoning, but it's never been a problem in Dead by Daylight, and that's a very similar type of game which has a bunch of licensed killers in it too (Michael Myers, Freddy Krueger, Leatherface etc.).
There are lots of people out there who prefer to go up against the killer rather than being the one playing them themselves, especially if and when they're playing with friends where that's their only option for playing together, so it's going to be rather annoying if it's just a crapshoot whether or not you get to play as the Predator in any given match in this.
The only upside over Friday the 13th is that at least here it's only 5 players per match instead of 8, so your chances of playing as the Predator will be a little better than the odds of playing Jason, but it's still less than ideal if they're going with that same system again.