I dont think people understand the ramifications of no T'Challa in this movie. Heck it took me months/close to a year to realize.
Its setting up to be a lose/lose situation.
Maybe the movie is great? Coogler is still a helluva filmmaker. There are people who think MBJ isnt a good actor yet Fruitvale/Creed are fan and critically applauded. Its not out of the realm of possibility he makes Wright decent enough as a lead. I ask again..why would they bring T'Challa back? Think of the anti-feminism claims.
Maybe the movie is bad? They could just easily pivot and say they see Shuri much better as a guest star in other films. Captain Marvel has brought in other "Marvels" to take the focus off her in the sequel. They can just place Shuri in other MCU films as the quirk side thing. "Retire" BP franchise for a while.
Its really looking like variant or no T'Challa for possibly 10 years. They'll simply move on. BP wasnt supposed to be as big as it was for Disney anyway.