I don't have a ton of confidence that the lineup you describe would be a particularly good team. That team doesn't have a credible go-to scoring option.
Bradley and Sullinger are nice pieces. Melo may turn into a decent player at some point.
But if we're talking about a post-Pierce/KG team, we are going to need a lot more young assets to build around. No, guys like Lee, Green, and Bass don't count.