My enjoyment of which was enhanced by the fact that, at the time I watched it, there was in fact a kitty in my lap who was indeed soft, warm, happy, sleepy, and purr, purr, purring. 
I like to be surprised by programs. It is very easy for a sitcom especially to walk down a well worn path of standard jokes. This episode shows the good and bad about TBBT in this regard.
The stoned segment mostly doesn’t work for me. Once I saw the cookies and heard the description of the women, I knew most of what was going to happen. “Deep thoughts”, a freak out that is easily stopped, munchies, instant amnesia, etc. The only part that was non-standard was the American accent references. (Which I see what other posters have noted as liking.)
Similarly, you have a setup with a guy with his eyes closed dressing a naked woman and you know perfectly well that the line “That’s not my arm.” is coming.
Sheldon and Penny filling out the form in the emergency room, OTOH, didn’t have much that could be predicted. I knew when Sheldon was walking back to her with the form that it setup an awkward/bizarre exchange with Penny. But beyond that it was hard to see the lines coming. So that part was interesting to watch.
This show is best when it avoids predictable bits, worst when they recycle decades old cliches. If they can do the former, why are they doing the latter?
My guess is that the show’s writers are trying to keep the show accessible to the masses while catering to die-hards.
It was mostly a good episode. The guys being stoned was funny at first, especially Raj laughing at their accents, but got old quickly. Still, I laughed more at this episode than all the other shows I record.
If he had come in in the next line, the two melodies would have been too similar and wouldn’t have made a good round. It didn’t make sense for Penny to tell him to come in then. He came in at exactly the right point.
You’ve summed it up perfectly.