I don’t think any one has a huge emotional attachment for Thunderbolt Ross in the MCU. Recasting him isn’t a big deal.
Chadwick’s depiction of T’Challa does. I honestly think just slapping a new actor into the role would be fairly shallow… because of the death of the actor.
But, the role of the Black Panther was meant to pass from one person to another. It makes sense that it goes to another actor/character.
BUT - as pointed out in the OP - T’Challa did come back from the dead. So, I think a future film could incorporate this plot-line. Which would then explain why he looks different.
