Its a tough question and i don't think the Kawasaki Bosses even know the answer yet.
DePuniet has more raw Speed than Westy and is clearly very talented, but if he can't relax and stop crashing he will not get a ride he is clearly capable of justifying.
West is learning fast and catching up to Randy, his worth in the long run will be more clear as we see his learning curve level out. But when will that happen, if he stays at this rate for the entire season he will be good for podiums next year, but i doubt that will be the case.
Overall i've always had a soft spot for DePuniet since 250 days so i hope he gets it done (and beats Hopper next year), but i actually fear that West will prove to be the better man.