Hmm, but it didn't work out because Duncan chose to remain in San Antonio and Hill was injured.
Had Duncan signed in Orlando and Hill been healthy, would it have worked? I think so, since Duncan was a dominant inside force, McGrady was a dominant perimeter force and Hill played more of a Scottie Pippen role on offense...able to score at need, but also willing to pass and facilitate the offense. The three players seem to fit well together.
I think James/Wade/Bosh could work, though they don't fit quite as neatly. There's a lot of overlap between what James and Wade do and a lot of overlap between what James and Bosh do (James is such a freak). I think they'd probably win a title, because it's just hard to imagine all that talent failing, even if they weren't all optimizing their abilities. But I think there'd be a lot of clashes, especially after the first title.
Of course, the first three-superstar experiment didn't work...Jerry West, Elgin Baylor and Wilt Chamberlain. The Lakers only won a title, as I recall, after Baylor retired and it was just West and Chamberlain.