I actually think we should go an extra step and split even further so that each type of scientist has only access to one area of science with the exception of the experimentor that would be tied with RnD access.
So, for instance:
Scientist: as you sugested, RnD and the Experimetor
Chemical Reaseracher(since chemist is the guy from medbay): has access to only scichem
Plasma Researcher: has access to toxins
Xenobiologist: has access to xenobiology
This should encourage scientists to actually cooperate instead of doing everything themselves and hopefully fix the issue of "no one is doing rnd" since there is a role specificly for it