The movie was good and every character felt like they belonged. Chad gave a great performance but he died and it changed the whole focus going forward.
The plan to use Shuri instead of recasting was bad in foresight and hindsight. A lot of us in this thread said they should re-cast and we didn't even forsee the problems they are having right now.
It wasn't because T'Challa was a weak character that they didn't recast, in fact it was the opposite. Chad was so good in the role that Marvel Studios that they would honor him by not recasting which was a huge mistake.
Delay the movie, let time past and everyone grieve. Then find the replacement.
Instead, we get a delayed movie with a problematic lead and a lot of uncertainty. That's because Marvel Studious misread the fandom.