They would have been really weak at the 2, but their frontcourt would have been versatile with Hickson/Bosh/Varejao/Jamison and probably Zydrunas.
The interesting question is, if they got Bosh & kept Bron, do they still trade Mo for Baron + pick, which turned into Uncle Drew.
If they had pulled that shyt off

Kyrie (on a rookie deal), Bron and Bosh.

Now that really wouldn't have been fair.
In order to get Bosh, Hickson and probably sideshow would've had to go back to TOR most likely though.
To answer the question I couldn't definetely see Bron and Bosh winning titles in Cle. All Bron was missing was that second dependable option (in the playoffs). I'm not sure why people act like this was a possiblity though. Cleveland had no cap room so they would have had to do a sign and trade and Bosh would have to agree. Why would Bosh chose to play with Bron in Cleveland when he had the option of playing with him and D. Wade in MIA?