Unfortunately BP and TR share the exact same plot. Both deal with the death of a father and the ascent to the throne only to be usurped be an unknown family member and then trying to grow into the responsibilities of becoming what they need to balance shirking old traditions and maintaining the spirit of their kingdoms. Thor realizes that he must let Asgard the place be destroyed in order to save Asgard the people and he finds his true powers. T'challa realizes it is time to bring Wakanda out of hiding in order to help his "people" and the rest of humanity. So there's that.
In the end and in my uneducated opinion, BP is the better movie. And it all comes down to Bathos. TR while great, felt like one big joke. And really, it should have been a little serious. Thor loses his dad, his best friends, his home, and is cast into a junk planet. And they joke the whole time. Almost every serious scene is undercut by a trivial joke. As an example:
Black Panther is the better movie because while there is humor it doesn't take from the seriousness of the film. And yes, I know what you are thinking, how is a comic book based movie supposed to be taken seriously? Just go with it. T'challa's story has some humor. His sister is the genius/comic relief but at no point does the humor take away from the dramatic moment. By the TR and even Guardians of the Galaxy equation, the moment that T'challa takes his dying cousin to see the Wakanda sunset, someone should have said something to lighten the mood. But I would have lost my mind if that would have happened. Because it wouldn't have needed it. It is BP's drama that makes it the better movie.
The second factor in BP being better than TR is the villains.
TR's villain Hela is bland and one dimensional. Take over the world kind of crap and then move on to other worlds. Blah blah blah.
BP's villain has a similar objective, liberate the oppressed across the globe with the might of Wakandan technology. But there's so much more to Killmonger. While a MIT grad, and lethal SEAL with thousands of kills, he's still the little boy that found his dead father. He has a conviction that his cause is as just as T'challa's.
So with a complex villain and almost no poorly timed humor. I declare Black Panther the greater movie.