Never has there been an extreme and jarring case of scaling (
within the same series, so no, Olimar isn't a counterexample) such as the idea of the
giant monsterous Ganon being scaled down to be closer to the rest of the Zelda cast. The closest case would be in regards to Pokémon, and how the size gap between the likes of Pikachu, Jigglypuff, and Lucario and the likes of Mewtwo, Charizard, and Greninja was made smaller (with Pokémon Trainer's presence in Brawl implying that the former three (and Squirtle, Ivysaur, and Pichu, technically) are actually
scaled up as opposed to the latter three being
scaled down).
And Ganon using "various magic attacks" and using the trident is one thing, fighting like he does in the actual Zelda games is
another, however. We can't have a quick, projectile-spamming, constantly teleporting around, large heavyweight with high damage and strength output. He'd have to ironically be like his Gerudo counterpart and be really, really slow, but have power to back up his attacks.