Shuri's power is different from what we've seen of the KOTD. T'Challa can talk to previous BPs, but Shuri has the ability to replicate the superhuman powers of any previous Wakandan in history. The obvious difference I think being that Shuri actually needed super powers since she didn't have any anymore, while T'Challa didn't aside from repowering him to roughly his previous levels. Coates upgrade to Shuri did more than Hickmans upgrade to T'Challa because she needed it more.