I think the best way to describe Thor Ragnarok is by treating it as the third campaign by a relatively new group of Dungeons & Dragons players. Twice now, they've been heroes. Twice they've been defeating monsters, exploring dungeons, and saving the people. There've been good times, there've been bad times. Yet somehow the experience was not exactly what they've expected. For them it feels like they've been going through the motions. Moving up to a target, rolling dice, and hoping the end result is whatever the win state is. And yet, what more could there be to it?
Roleplaying, that's what!
And like a bunch of min/max-ing players finally having seen the light, Ragnarok embraces all of Thor's flaws and finally starts to play with them. Not playing but actually playing.
Thor is a bit of a bumbling fool with a heart of gold? Sure, let's up the ante on the bumbling. Loki really can't help himself in betraying his besties? Gotcha. Competent villains drank their own Kool-Aid a bit too much? Can do! There are even some self-induced flaws and difficulties that crack the foundation of the previous Thor films, throwing kinks in the cable and actually propelling all character arcs forward.
It's in the interplay of letting characters loose at each other that the magic happens. Ultimately the atmosphere and sheer energy present remind me of More Then Meets The Eye/Lost Light, a Transformers comic series that did a similar thing. It took the core aspects of each of its characters, made them into caricatures that they each had to deal with, and put these against a backdrop of epic proportions.
The result was genuine humour with characters finding their natural friends and enemies. Stakes were actually getting raised to the point that heart strings snapped. Oh, and you know it was a joy to read.
Ragnarok follows this principle for the most part. The heart strings aren't pulled too much. Most of that is done by Odin, basically taking the previous two films with him as he exits the stage. It's OK though. Ragnarok needs to get rid of the old to let the new grow.
Made you look
A side effect of putting the characters front and center is that everything else either slots into place or is subtly ignored. There are some weak points, but because the rest is so good, you'll gloss over them. Compare to the previous Thor films, which were so bland, that every minor problem started to stick out like a sore thumb and you needed to punch yourself into a state of disbelief not to be bothered by it.
Ragnarok in contrast, manages to put you in that state merely within the opening scene and then simply doesn't let go. There are references everywhere turned into jokes of varying strengths and just about every one of Chekov's guns goes off. You don't know when exactly, but it's always a joy to see one spring into action, neatly making even the most deus ex machina solutions look at least logical while completing the story's circle.
Ragnarok is good. No wait, it's great. It's the best Marvel film since this entire charade started, blasting past the enforced seriousness of The Avengers, the Saturday morning cartoon vibe of Guardians, and the war wounds of Captain America. At the same time, it pays homage to them and wraps up a satisfying arc with a level playing field to start anew with.
The film may be flawed, but by Odin, does it know how use those flaws to leave an impression.