KG is what he is at this point. He is about a borderline All-Star who can do damage against most guys in the league, who still are either too small, or too slow to keep up with him (like Jamison, Beasley, etc), but he can no longer shut down, or dominate the truly elite big men such as Howard and Gasol.
But KG is getting a little too much blame for last night anyways. The real problem was on the perimeter. They were allowing way too much penetration, which was forcing KG and Perk to lose position, and letting Gasol run wild underneath. Now, the bigs are not without blame for this, because they were constantly late on their blitzing on the perimeter (honestly, the guys who were rotating the best were Davis and Sheed in the second half), so it really was a team effort.