Bradley isn't going to be a top 3 player on a title team, but he certainly could start for one. Most title teams have one or two role players that start.
He has made some nice incremental improvements as a passer and decision maker this year although you will never be able to run the offense through him.
I'm more than a little disappointed he hasn't made more of a leap forward this year with efficiency of his offense. Part of that is due to the limited types of looks he gets. Stevens offense has taken away some of his back cutting options, and he rarely gets easy looks created by the other guards. He's actually being defended as the team's first or second option right now. I think he'll be more efficient on a team when he's the fourth or fifth option.
What he is is a great defender who has to be covered and can occasionally go off for 25 points. He's also still improving incrementally and should become somewhat more efficient as he gets older. There are a lot of defensive role players in this league who play major roles for good teams that can't contribute on offense any where near as much as he can.
He's also a good, hardworking guy who leads with his effort. At the beginning of game two, he had some defensive sequences against Kyrie Irving that were incredible. The league wide trend of overprotecting ball handlers has hurt him some, but no one in the league can play elite dribblers as tight as he can.
He's a solid, useful starter, but not a star. He's the least of our problems.