I think the main criticism people had was not the idea behind the plot, but the fact that it messes with the first film.
If they had kept the idea:
* Rogue Predator being chased by Arbitrator across space and hides in a jungle on Earth.
* Arbitrator hunts Rogue who is killing humans in the jungle and kills the Rogue.
* Humans mistake Arbitrator for Rogue and attack him, forcing the alien to defend itself and take an opportunity for a little hunt since he's already on a hunting ground.
But with no connection to Arnold or the first film. It could be somewhere in South America, during a drug war. Or it could even be on a topical jungle like South China Sea was, there's lots of jungles to pick from and conflicts with various human factions involved. It could even have been 'Nam where the Rogue attacks Viet Cong and American soldiers.
The Arbitrator could just destroy the Rogue via its self destruct and then be mistaken not due to "taking his gear back", but simply due to looking non-human and being attacked because his description would match the Rogue. How would the human characters tell it apart from the Rogue due to its otherworldly appearance? They won't care, they see Mr. Tall n' Scary and they attack it lol.
That was another gripe about the plot of the novel, Rogue and Anytime would have a virtually identical appearance in basically every way. While if this had no connection to the film, our imaginations would be able to fill in the descriptions of Rogue and Arbitrator.
