Doesn't sound boring to me, sounds
great. I'd much rather play a game that's difficult but allows me to learn and adapt, therefore creating an entirely new experience as I have to play this shooter differently than all of the others due to the unique enemies, than a game that holds my hand at every opportunity and makes things unrealistic for the sake of easier gameplay.
That's the whole point of playing an Aliens game, that you get to fight Aliens and they're different and unique and scary and demand a
different playstyle and learning/developing new strategies to beat them that you wouldn't have in a standard shooter.
Punching just makes them into more space raptors. Hell, you couldn't even punch a raptor, contrary to the stupid scenes in movies. They would simply bite your hand/foot off if you tried.
Melee is fine in most shooters with human enemies, or zombies or something, but Aliens are a different story.
You shouldn't need melee bs for gameplay variation. You should be plenty busy running, using your tracker, shooting, learning how and when to apply grenades, welding doors, avoiding ambushes, avoiding acid, trying different weapons, using sentries, etc... Plenty of authentic actions to make gameplay interesting.
Coordinating with a squad of marines would be the most epic, with the pulse rifles engaging Aliens at long range while the flame units/shotguns crouch beside them, ready to suppress those Aliens that get close, or something like that. But no, we can't have something
that cool.