This kind of facility is very much needed and I very much support your suggestion.
There is a complication that needs to be taken into account. Namely, the current RM design conflates its one and only "profile" for sentence templates with its one and only "profile" for GEDCOM export. For example, the Fact Type entry for the Birth fact defines how birth sentences should look in reports and also defines the conditions under which the birth fact should be output in different media such as GEDCOM, narrative reports, etc. So if you change this design (and it does need to be changed!), you need to take everything into account in the design of a "profile" system, not just GEDCOM.
When I have talked about this situation, I have talked about it primarily in terms of sentence templates and I have used the term "styles" rather than "profiles", but it amounts to the same thing. In my view, the sentence templates could be set up so that there would be a Terse style or a Verbose style or a Point Form style or an English style or a French style or a German style etc. The same sort of thing is obviously needed for GEDCOM export, and whether it is called a profile or a style makes no difference. However, the options for GEDCOM should probably be separated from the options for sentence templates instead of remaining conflated as they are now.