OMG! The old discussion about Historians, Linguists and the like being scientists or not!
JP is, in my opinion, a well-known scientist: research, publications, a tenured position in a top-class university, chair of a university department; Marcel is a professor in Montreal and that means he has some research to do as well... Science is not defined by the object of research, but by the way of approaching items and trying to find out how to get to the core of things, regardless whether you deal with marine biology, wildlife, history, laws or languages!
Anyway, I agree with you that having a CAP character working on a different field of science would open new paths to the CAP-world: new topics, new problems, new interests. No doubt there, Mark will make a wonderful job as usual.