You do not simply take one of the best movies in the history of movies and say it would be a better movie if it had Aliens or Predators in it...
HMMMM let's see. Cloverfield would have been more interesting if in stead of those little snappy things there were Drones and Facehuggers falling out of the creature's chest, because that creature had stumbled upon some old eggs under the sea and somehow a hive had established inside its body, using the many and huge organs to breed an enormous amount of drones so that now the creature was full of Aliens, eating it from the inside, and in such great pain that it went on a rampage.