I just flat out don't believe, barring extreme circumstances, that an organization or coach can "ruin" a young player. If a guy has it in him to work hard and succeed then he'll eventually do it. If he doesn't then ultimately it's his own fault, whether by lack of talent or a bad attitude.
If anything, Grigorenko should learn from his lack of success so far in Buffalo and perhaps build off his success in the WJCs. If somehow the process he's been through has actually hurt his progress, then he doesn't have much chance at overcoming the adversity he'll face in the NHL. An organization can screw up and push a guy early or hold him back too long, but making or breaking a career is on the player.