Overall this season's been pretty good but it's probably the right time to end as there's not many places to go with the character development and the dynamic of the team isn't fresh. The shows having to rely more and more on the cases which was never the main attraction.
Don't mind seeing the show end to be honest, but like with Entourage and Ari Gold, it's a shame to see a perfectly formed character go. Hopefully they write in a strong ending, wouldn't surprise me if he dies trying to save Wilson or something.