I've run across something in recent playtesting for classes I've been designing and I wanted to get the community's opinion on it.
A class I recently designed is a martial buffer (full BAB, medium armor, 2 good saves, 4+Int skills), who at level 2 can choose a specialty (Medic, Scout, Soldier, Artillerist) that allows her to cover a secondary role of healer, skill-monkey, tank, or controller (respectively). One of my local playtesters told me that he and his group were worried that this gave the class too much versatility and that you shouldn't be able to build an entire group out of one class with all of the roles covered. My initial response was that it's actually easier to list the core classes you can't build a group out of with every role covered than the ones that you can (my personal list would probably Fighter, Gunslinger, Rogue, Samurai, with the note that you can actually build a reasonable 4 man group from Rogues and possibly Gunslingers, you just wouldn't do it in a way where you have all 4 roles covered).
The thing is, this isn't the first time I've heard this. In other playtests I've seen this come up before from multiple parties, this idea that if one class can be built for any role it's too strong, even if you can't actually fill all of those roles in one build. What are everyone's thoughts on this? Do you think it's a selling point or a point of concern when a single class has the potential to fill any role in the game? How does that jive with the fact that there are already so many classes who can do so already?