Easy way to improve Drift, have him screw up royaly. The chracter just seems to perfect as is, as said above he needs some flaws, and to fail all the other Autobots have.

And then after failing he commits seppuku, no wait just kidding but he should fail.

I'd like to see him actualy get a nemesis who can actualy defeat him, a Megatron to his Prime so to speak. Bludgeon would be a good candidate as he's been around for a lot longer and has always been portrayed as a master of Metalikato. Does anyone even know what sort of martial art Drift practices?