Sure alot of Aliens got killed in Aliens, but they were also going up against trained soldiers with serious fire power...and were still almost completely annihilated save for Bishop "who isn't even human..and still torn in half by the end of the movie", Hicks "pretty much crippled from burns", Newt "Luckiest bitch alive", and Ripley who at that point and time knows more about the Xeno's then most people cared too..even though that did little to help her situation when you really think about it.
I think the whole Elite Predator thing would of worked much better if they at least made it seem like he had his hands full. If a Predator had enough experience hunting Aliens like Wolf was supposed to have had...he very well could have survived an Alien attack...but that doesn't mean it should of been easy....You never even once got the impression that he was even breaking a sweat. The action scenes should of been fast paced and hectic because he should of been being attacked from all angles with only fractions of a second to respond to each Alien. Every move he made should of resulted in a crippling blow that would at least knock an alien back, or a kill. That spear could be the perfect weapon for at least keeping Aliens at bay. But apparently it's too much to ask for a Predator to move even remotely as fast as humans obviously can and actually fight with the damned spear instead of just stabbing with it.
He just seemed WAY to eager to get right in the Aliens face which should of been the last place he wanted to be... That sewer fight scene could of been the greatest sci-fi battle scene in recent history and it ended as a dud.
Either way rather he fought like he should have, or in the way it actually turned out in the movie.....he should have been seriously hurt in the end of that fight. Doesn't mean he had to get killed, but he should of at least caught a tail through the shoulder or a claw across his obviously unarmored stomach. He should of been more of the "Takes a serious beating, but still somehow comes out on top" type than the "I can do this all day" type.
Sorry, done writing novels this is all of course IMO.