Bass is sort of like Krstic in that he's an above-average backup who isn't good enough to be a starter on a championship contender. (Other than noting that they are both bigs who can make jump shots, I won't claim there are any other parallels.) I mean, yeah, he might be tolerable as a stop-gap solution if he is surrounded by better players, but you're looking for an upgrade.
He's certainly an option for the fifth guy in end-of-game scenarios. I think his free-throw shooting ability should make him an offensive upgrade in the fourth quarter. He sounds like he will get his shots because he will move and get open, rather than teams being willing to let Davis take shots.
I'm not going to treat Bass as the magic bullet who makes the team clearly better, but I have a hard time seeing him being a downgrade and he's much more than I thought was possible in a S&T for BBD.