>>40826971>Why don't just blend in Z-moves and Megas? Make Pokemon gain access to a specific Z-move by mega evolvingBecause they are a different mechanic. This is IMPORTANT.
Megas give the Pokémon a stat boost and in some cases, change their ability which changes their playstyle (e.g. Heracross) or change their type which changes their positioning (e.g. Charizard). Lots of Megas can still be defeated by their normal checks.
Z-moves are a different mechanic that relies on the fact that Pokémon can learn different typed moves than their own type(s). Z-moves can be used to either deliver a devastating STAB attack, set up with multiple stats in one turn, or catch the opponent off-guard with an unexpectedly super-effective move.
Gigantamax is interesting all on its own in that there's a time limit and presumably you wouldn't want to fight one with a regular-sized Pokémon. If it's the halfway-house it seems to be between Megas and Z-moves, it could still be an interesting mechanic for 6v6 battles that isn't just reverting to weather wars and walls.