Chang was definitely better when he was just a bit crazy, but still grounded.
The most recent episode felt like they tried to fit way too much into 21 minutes. It was also a bit too 'out there' for a non-theme episode (theme episodes being ones like Paintball, Law & Order, etc, and I would count ones like the recent dreamatorium episode).
They should also cut back a little bit on the Dean and his outfits too. Jim Rash is awesome, but it's getting to be a bit much. The one a few weeks ago where he realized he had gone too far seemed like the perfect cap to that joke. The joke this week was funny on its own, but in the scheme of things, may be overdoing it a bit.
That said, this episode was still okay. The show has just set a very high standard for itself. For the most part, this season has been great, and the first two seasons are amazing.