It was a fairly good sequel to a movie in which the main character is dead irl, but there were many things Disney could have done better.
1) The main antagonist. The main antagonist, Namor, could have been both written and designed better in both my father's and I's opinions. He seemed, to me, very last minute put together and not fully fleshed out.
2) Ironheart. While the way they introduced Ironheart was pretty cool, it seemed very camouflaged and if you didn't know what or who you were looking at, you would just see another person trying to imitate Tony Stark's Iron Man armor. They also never flat-out said who she was.
3) The ending. The ending was to me pretty lackluster, and to my father and I it didn't seem like the actual end. When Namor yielded to Shuri and ended to war between Wakanda and Talokan, it didn't seem like it was really over. Namor said that he'd be their ally for now, and he put emphasis on the words "for now." This leads me to believe that there will be a third Black Panther movie in which some other country decides they want Vibranium for themselves, and attacks Wakanda. When they attack, Wakanda will call upon Talokan for reinforcements, but they will never come, and Wakanda will fall. When they fall, Namor will lead Talokan against the attacking county and take all the Vibranium for himself and his country.