Ray off the bench is not a good idea in my opinion. The so often stated "scoring punch off the bench" is nonsense, it's not what we get from Ray, since he needs someone who can pass him the ball at the right time at the right spot (Rondo). He is indeed a one-dimensional player these days so we need that one dimension to be as much effective as it can get.
You all saw that Ray can't do much more than hit threes and spread the floor. Plus, when the BIG 4 was on the floor together this season, we were the better team in almost every situation. There's just so much chemistry between those guys, and I think Ray is a big part of that.
If you want scoring punch off the bench, Pierce is your guy. He's the one who can score on his own, not Ray. In games where you need to defend your leads, he will deliver some baskets when you need them!
My suggestion would be to sometimes adapt the starting lineup to the opponent. If we're facing a team with a strong SG like the Heat etc. , you start Bradley for defensive purposes. If you're facing a team with a weak SG, you start Ray, he will be much more effective and possibly won't have to defend the ballhandler very often.