Even though Monkey Island now has a real (i.e. canonical) ending, it sucks. I prefer the original continuation of MI3 to the 25-years-late official, canonical sequel
The link given elsewhere here about the multi-layered aspect of the stories from 1, 2 and RMI gives it a bit more depth. Obviously if you take it on the surface level only it's low effort.
It's not just the ending, but the flat humor, the lazy puzzles (like clicking multiple times on multiple objects to open the porthole) and the meagre number of interactions on each of the islands after the first one..
It's like his heart just wasn't in it anymore
It felt like a "ehh let's get this over with" at best
or a medium-effort nostalgia-pandering money grab at worst.