Pred is definitely not nerfed. He actually handles quite well in the right hands. I do about as well with him as I do the other two (around 3rd and 2nd place usually), and even won a round with him.
Seeing other preds in heat vision makes more sense than having a separate pred vision, as we see the predator looking at his hands in the first movie and he's just as red as the humans he's watching.
Lights can all be broken, I've seen it done.
The spear (combi-staff) replaces the spear gun. You can't melee with the spear, but it can be tossed to great effect. It serves the same exact purpose as the spear gun, just a little harder to utilize (I'm rubbish with it), but from successful users they say it's infinitely satisfying.
Also, the targeting laser giving your position away doesn't mean you're dead. If you hit what you're aiming at, it means that's the last thing your prey sees.
There's no plasma pistol, but isn't that what the shoulder cannon's for anyway?
The only thing I'm sad to see missing is the netgun. Man that thing was cool. Of course, it poses its own balance issues, and the marine no longer has a knife to cut himself out, but still, what the pred has is good. You'll likely find yourself gravitating towards either the disc, shoulder cannon, or the wristblades.
Nobody got nerfed. They all play wonderfully.