Can we first start with some baselines on what a championship level team has? To me it has to have:
1) Defends with Size (see Lakers, Celtics, Magic)
2) 4th quarter closer (Kobe, Pierce/Allen, Duncan, Deron Williams, Chauncey/Melo)
3) Has some way to get buckets in the paint when needed
4) Will net more possessions than opponents (by outrebounding opponents, steals, blocks, etc)
5) Excellent ball movement (either through several players that know a system like the Lakers, or through individual point guards that can get it done like Deron Williams or Rajon Rondo).
To me, Bargnani might help with #2, and with #5. He doesn't help with any of the others... and is he really that big of an upgrade over Turiaf? Turiaf helps with #1, 4, and 5... Do you see how bad we are when Turiaf leaves the game? We really have no replacement for him on our roster.
Bargnani is not the answer. Now, if Stoudemire was more of an intimidator type power forward we might be able to get by with a skill center... but we can't have finesse type players at both Forward and Center spots. It won't work come playoffs.
Rose is not the answer.