We still need to define the KOTD power set, right now he seems no different than from pre KOTD. He's supposed to be physically better than with the HSH but doesn't really have the feats to prove that. Pretty sure he could already talk to past BPs the only difference is that we get to see it than it being like an internal thing. Still not sure what the spear Coates keep using is even supposed to do, so far hasn't done anything that an energy dagger couldn't.
More needs to be done with the necromancy side of it. The zombies from Secret Wars only followed him because Namor killed one of them. Shuri has gotten a much better feat when she created and controlled Jabari zombies. I believe she has done that twice, once in season 2 and the other in Ironheart. Eden's help was needed for T'Challa to summon the past BP spirits to fight at the end of season 1.
If it were up to me I would've tried to make sure that it lived up to the hype. How the powers of all past BPs would physically put him way beyond his usual weight class, I'd make it akin to the Avatar state where he can draw on the past powers and experiences when he needs it for a short period of time, reserved for heavy hitters.
He should be able to spiritually and physically enter the djalia, ancestral plane, or any other kind of underworld at will. Make the spear used specifically for the dead/spirits. Being able to create and control zombies is something he should be able to do and not Shuri.
Summoning past BPs to fight should not have required Eden. Also have the past BPs actually give useful advice since the only time I can recall them doing so is when the queen told him Zavawari was alive.
As of right now I wouldn't care if Ridley or any future writer decides to throw away with it since it's just wasted potential.