Shuri became Black Panther in the comics, so it's not coming from out the blue. Now this Shuri playing Black Panther is another story. MBJ playing Black Panther does have some logic given the story in the movies. But I wasn't a fan of his acting really. Given that BP2 is being filmed and probably released so close after his passing, it's in good taste not to recast BP so soon. I'm sure a royal b*stard will pop up sometme during BP3 or BP4.
I'm willing to give it shot. I think people don't want her to be BP because she's too petite. Take away that, and nobody would have any problems.
She has royal blood
She's a genius
She created BP's suit
She has personality, and stole scenes in the first movie
She fought in End Game
So it should be a no brainer
Recasting at this point doesn't make sense, and the actor and the vibe of the movie would always been overshadowed by Boseman's legacy. The only way to truely pay homage is to go on without T'Challa and build around his loss.
Recasting would literally act Boseman was NEVER in the MCU. They wouldn't be able to mourn is loss on screen. You gotta realize the characters would treat the character like he never so they wouldn't be able to acknowledge the loss.