Jeff acted like Jeff, Brita acted like Brita, Abed acted like Abed...but the humor was just a string of quirk-driven gags, rather than being driven by the characters' emotional state and psychological history.
I think you're being overly reverential to Harmon's Community. The best gags are the ones you mention, and they're the ones that fans remember most, but it also had a lot of standard jokes and random quirkiness.
The episode was fine. It was a fairly average episode of Community. If the rest of the season is like this then I'll be a little disappointed, but I know that Community often takes a few episodes to get going each season so I'm just going to sit back and see what happens.
Maybe, but here's a list of the most memorable Community episodes, to me:
1. Paintball 1&2
3. Alternate realities
4. 8 bit video game
5. Abed's claymation Christmas
7. Air conditioning repair showdown
8. Pierce is in the hospital and gives everyone gifts
9. Blanket fort
10. Abed is god movie
All episodes without a B plot, which took a crazy premise and just committed to it.
I'm very worried now this season is not going to commit to a premise like that, and is just going to play it safe with a lot of A&B plot episodes, which get the characters exactly right but are boring.