I'm afraid you have no argument there, there's no rational basis to suggest either Cilic or Raonic are overranked at the moment. It might be true that a good share of their ranking points comes from smaller events, but it's not like the guys ranked below them - or rather in the same area of the rankings - are getting any better results in the big events - well on the contrary.
No,I'm not suggesting they are overranked.But they both lack big results in big tournaments,especially Cilic.
So,everyone is a vulture one way or another
I like vultures.