I would honestly try to keep Ganondorf heavily same as current Smash type but give some unique moves.
DownB would be dive with Trident used by Phantom Ganondorf, instead of kick dive. Aerial version would be downwards poking move with keeping good shield breaking. UpB could be single powerful uppercut with super armor. No more copying Falcon grab-boom one. SideB is fine, and technically I'd be ok with NeutralB, although it should gain the symbol of Triforce of Power to look cooler. Up tilt should be performed by hand and be magic based instead of burning foot smash. Down Tilt could be small electric shock to ground to differentiate it more from forward tilt. Up air should be electric ball instead of sweeping kick. It would lose range but should compensate with power. Back air should gain Darkness magic properties. And neutral air should be a horizontal cape slash, that would uniquely reflect projectiles. I don't think any neutral air reflects at the moment? Of course, it should be fairly weak and not strong reflect. And grabs should have more unique animations like referencing punch from Wind Waker.
Would this be good enough? I didn't want to go too far like some Magic Ganondorf mods did.