I think G's versatility will be why the arguments drifts more toward Joseph over TC, than Joseph taking away minutes from G. When he replaces G, we still have Cooney out there, and with Cooney, as others have said, you know what you get. G and Joseph make up a more dynamic backcourt - and if the "hot issue" at the moment is a lack of play inside the three point line - well, those two are probably better suited for getting into the lane a bit and creating opportunities for others. That being said, I haven't seen that much from Joseph through three games...so maybe it's irrelevant.
Cooney gives us that stability you see from a 5th year Senior, but not much in the realm of creativity or taking it to the rim. Now, maybe we do see that at some point this season, but I remain skeptical he's capable. I tend to agree that he overthinks things though (as someone mentioned previously). He's so geared up to take a foul that he's almost flailing around wildly before he ever has a chance to get a shot up when he drives. I've never seen a non-Euro player (probably an exaggeration) that recoils so quickly from even light contact. He took a slight bump on the perimeter at the three point line yesterday and ended up near half-court...lol. If it's working have at it, but I'm not sure it's a huge benefit for TC. Who knows.
All thins considered, I would keep running out Joseph/Cooney/Howard wildly and see how it shakes out. I wouldn't just alot the minutes to TC based on seniority. Although ultimately TC's defense may be the driving force to keep him out there. He doesn't seem to be taking wild shots, or playing out of control - so, no reason to shake things up too much. The defense issue (Joseph/Howard's aptitude) will become clearer in games to come I suppose.