Thor ever taking itself seriously has often been its downfall. Movies, comics, anything. Asgard is ridiculous. Thor is ridiculous. All of its ridiculous. The tone of the movie is a far cry from Guardians too. Hell, most of the comedy is completely unlike Guardians... it's not James Gunn. It's Taika Waititi. And that's its greatest strength.
You could have made a somber, mopey, Thor out of Ragnarok where the world caves in on him and his very reason for existing is questioned you could. But then you'd likely be in the same boat as Man of Steel or BvS which I know you hate. Everyone has different tastes but you started out kind of trashing it without bringing up any points as to why it's bad. And then you brought up th ONLY reason anyone ever says it's bad. One reason. That's not really a critique at all is all I'm saying.