Without knowing this though, whose to know? I generally associate pluggins as something that I add to a program, not something that is added by default. It would have been nice if Adobe allowed you to choose the pluggins at install (maybe they do, and maybe I missed it or wasn't grasping what they were offering?).
Also, I counted 21 xxxx.api files in the pluggin folder. It appears that several of them have dependencies, as removing them on an individual basis may end up with Acrobat crashing -- definitely not conducive for the end user to tailor Acrobat to their liking. In fact, without specific knowledge of what api's can be removed without causing a crash, it is easy for the end user to assume that these are required by the program to function properly.