Personally, as much as I loved the rest of the game, the ending wasn’t for me. It’s not that it seemed rushed or random, just a bit tropey, like a vaguely modern version of “it was all just a dream” or something.
I didn’t know the anecdote that you mentioned about MI2’s ending so I googled it and came upon this old thread: Ron Gilbert about art and bad endings where Ron made some insightful posts.
Of most interest to me from the PAX speech, though:
I’m not saying that creating something everyone loves is easy but in some ways it really is the easy way out. If you want to create something everybody likes, take a picture of a cute puppy and a kitten.
So then one morning I was laying in bed and I was just staring at the ceiling and the ending to Monkey Island 2 just hit me. Not with all the details like the Star Wars parody but the basic gist of it and it just felt absolutely perfect; it was odd and it was strange and I knew a lot of people would have just hated it.
That’s why I loved MI2’s ending so much. It just went straight off the rails. Even today I don’t know what ‘really’ happened. TWP stayed on the rails and sort of recursively joined the rails back into a loop which was not as exciting for me. But I’m sure Ron expected such a reaction and isn’t too peeved.