Well the Alien does have a huge grabbing length for a stealth kill.. I've been using those cockroaches a bit more and it's pretty damn far.
They also need to fix the alien pounce to a knockdown on a marine cause it doesn't do jack sh*t. I knocked down 1 marine and that was when I was pouncing from a high altitude onto a marine below..
But about the pred knocking an alien down.. I realized it's fine. the preds can knockdown aliens for an easy kill and the aliens can stun preds with heavy tail on the wall or the ground. All it takes is 1 tail and the pred is stunned long enough for another one then just do a finishing move. At first I was considering it cheap but really, it's a tail so it's gotta hurt. So the way I see is, preds got knockdown, aliens got tail stun. All it takes is 1 of each to kill the other easily. So it's fair game to me.