They can have their acid proof weapons, if they keep the acid blood the dangerous factor in melee that it should be as far as I am concerned.
In one of the old AvP comics they depicted it perfectly. A young and inexperienced predator (Light Stepper?) gets pressured by an alien, he wants to end it quickly and decisively and goes for a decapitation despite it beeing very close to him due to inexperience or need to end it quickly because he is starting to get overpowered and gets royaly screwed because of the fontaine of acid blood.
To know when to strike without getting showered by acid should be part of the challenge.