Ok, but what purpose does it serve to have the enemy develop and kill you faster? Also another gripe I have with the first AVP was the ammount of Predators versus the Aliens. It was bullshit. I also remember the surviving chick sticking her arm in the Alien head and using it as a shield, umm.... I'm pretty sure her arm woulda got burnt off.
The predator ripped off the top part of the Aliens head, the top skull, and cleaned it off with something on his arm that looked like steam or something, washing the acidic blood off.
As for what purpose does it serve to have the enemy develop faster, the Aliens are not the Predator's enemy, they are the challenge and the prey. The Predators breed them and release them simply for the challenge, and if you read about Predator mythology, they are all about the challenge and the hunt.
If you remember in the original Predator movie, the Predator wouldn't kill people that were unarmed because it served no challenge, and then when it could have easily taken Arnold out it decided to take its armor off and fight him one on one with no technological advantages, even though it made it easier to kill.