I'll buck the trend---I thought the Bad Bloods were a bad idea.
The thing that made P1 different from other "monster movies" was that the Pred had a code that he lived by--he wasn't just a mindless serial killer who chose victims at random, but was a hunter, for sport. It wasn't really the kill that was his end goal, but the hunt itself.
The concept of "Bad Bloods" just returns them back to boring serial killers with no point or purpose, and makes the franchise just another series of slasher flicks. Yawn.
That's one thing I didn't like about "Predators"--the Preds there were not "hunters", they were more like terrorists or guerrilla fighters.
It was a complete retreat from the original concept of the Yautja.