Donadoni represents to me the antithesis of Capello, which might not be a bad thing, IMO, after two years of Capello.
Whereas Capello represents formality, structure, experience, accomplishment, and also predictability, rigidness, and less to prove careerwise ... Donadoni represents youth, creativity, strong player relations, and a hunger to prove himself. But certainly a lot less to show for it with a team of the stature, and budget, of Juve's caliber.
Yes, Donadoni is not proven ... especially when we compare him to the likes of Deschamps and Prandelli, whom most of us initially dismissed as too inexperienced when Capello first took the Juve reigns. But there's something about Donadoni I really like. He seems to have that grit, young industrialness, and faith within his players the way that Rafa Benitez or Deschamps have proven themselves to have in a few more years. But Juve is not Liverpool, and Donadoni's track record is nothing like even Rafa's brief coaching career at Valencia.
If we're committed to making a break from Capello, however, it could work. But there should be other more established options to consider first.
I still have mixed feelings about bringing back Lippi for a third stint. I feel that relationship has run its course, and sometimes it's best to leave the past in the past and move forward.