Though I find this game enjoyable, I feel it lacks longevity. It NEEDS more gamemodes and maps or it will go the way of Friday the 13th where people slowly lose interest. Having one game mode for this particular game's entire lifespan is a poor business model and a surefire way to doom this product. The different classes and weapon combinations can only take the experience so far before the playerbase takes their business elsewhere to get a more interesting and diverse experience.
My suggestions:
1. A city map similar to the environment of the Predator 2 movie. The special forces team will instead play SWAT/Police officers and undertake tasks around the small section of city while the Predator hunts them similarly to the base game. This would at least give the players some new locations with a difference atmosphere to keep things interesting.
(Another map idea would be the whaling station in Antarctica from the 2004 Alien vs. Predator movie or even the Pyramid from the movie. They are fun, new locations that give the players a change of scenery.)
2. Single-player challenges. This was something that Friday the 13th had and I at least applaud it for that. Giving the players single-player challenges where they play as the predator and complete solo objectives will let them play as the predator without long wait times and allow for interesting scenarios. Hunt a certain animal, take down a boss creature, kill these NPCs in a certain way without being detected and so on.
3. Custom Games. Letting players have custom games with modified conditions usually adds a few more years to a game's lifespan. What if the players want to play as 4 predators against a single, super-buffed, terminator marine? Custom games would let them do that. What if players want to do a free-for-all predator battle? Custom games. What if they wanted to fight waves and waves on NPCs to see how high of a score they could rack up and having the player with the highest score win? CUSTOM GAMES. Sure, people would create some weird stuff, but if they're having fun with the game I see it as an absolute win.
In short, fun for a time but needs new content to keep it alive.