I think this is a layer of complexity the game doesn't really need, although I guess some kind of Ki/PL drain attack with Cell's tail might be a feasible thing to add at some stage.
Cell does not need to absorb somebody in the shows aswell; he just needs to get a certain powerlevel which he can reach most easily by absorbing the androids. You know, he was perfect without 18 in the end
No . . . androids 17 and 18 were integral to Cell's transformation process, at least in the way that Dr. Gero had originally designed it. After Cell self-destructed, in his bloated imperfect form, something changed in his genetic structure when he reformed, something Gero hadn't planned for. He then returned not in the original perfect state, but instead as somekind of super or ultra-perfect Cell.
One of the interesting ironies in DBZ (there were many) concerned Krillen's decision not to deactivate Android 18 when he had the chance. Had he done this Cell could not have achieved his perfect state, backing up the claim that he specifically required the female android to transform.
Remember as well that Cell himself said that he could've absorbed Piccollo, who was at the time at least as powerful as Android 17, but chose not to because he already had everything he needed of piccollo's cells. Perhaps the other powerful characters (Goku, Vegeta etc) would have been useless to him for the same reason?
![[SSj]~Piccolo](/data/avatars/m/1/1185.jpg?1554280631){kind=avatar}