In his defence, Monkey Island is Ron’s creation and the ending is probably what he always intended. It felt like a fitting conclusion to me that neatly tied a bow on the whole saga.
Having said that, RtMI feels like Ron Gilbert telling me to go away and do something else with my life. The world is falling apart, the game characters don't care, the ending itself gives up on you and, in case you didn't get it, there's a letter afterwards from Ron Gilbert himself telling you that, if you try to recapture the past, "you'll sort of get what [you] want but it won't be what [you] expected".
As far as I'm concerned, I would have preferred it if he hadn't made the game at all.