He's not a kwame, darko type of bust
To me he is exactly a Kwame-level bust. The few strengths each have are just in different aspects. Kwame was younger, a better defensive player and rebounder. Bargnani is a better offensive player. But after 2 years, both have been near useless.
And the only way Bargnani will make or break the Raptors is in terms of what the Raptors trade him for. He clearly has no future in Toronto. He will never be an effective C and will never displace Bosh at PF. Even if he turns into a solid player, why keep him and not address the holes on the wings?