>>52146673Because the designs are cool, it helped out a lot of Pokemon that needed it (obvious shilling aside) and nothing else they've tried has topped it since:
Z-Moves are just nukes with funny dances in a game where nuke moves already exist (Fire Blast, Solar Beam, Blizzard, Hyper Beam, V-Create, Explosion, etc.), making them somewhat redundant. It also sucks that certain mons, such as Kommo-o and Ultra Necrozma, were entirely reliant on Z-Moves being a thing, since the former needs it to be competitively viable and the latter needs it just to exist, which sucks because I really fucking love Ultra Necrozma and I hate not being able to use it
to soothe Necrozma's constant headaches and bring him temporary peace Plus, it just isn't as charming as Megas overall
Dynamaxing is a combination of Megas and Z-Moves and inherits the best and worst of both. It can be powerful when used correctly but it's restriction of your mon's movepool makes it somewhat uninteresting. The designs for each Dynamax form aren't as good as the Megas (With the sole exception of fat Pikachu, which should've been an alternate form for normal Pikachu exclusive to Gen 1/2 traded Pikachus), and each form only lasting for 3 turns gives them a sense of impermanence that Megas didn't have, despite Megas only lasting until the battle's over. Furthermore, getting the Gigantimax formes was a massive pain in the testicles prior to the Isle of Armor DLC so I never even bothered to find them
Terastallizing is easily the best gimmick they've introduced since Megas: Changing your mon's type in exchange for it having to wear a silly hat all battle is a wonderful trade-off and I hope this carries over to future games (even though I know it won't)
TL;DR, Mega Evolution was a simple, straightforward and very charming gimmick that gave us some great mons to use in battle with cool designs like pic related
I miss him so fucking much ;-; 