>XY has some focus on megaevolution, a battle-only super mode with a different design for pokemon>ORAS goes deeper into its lore and gives Rayquaza a mega, as well as giving Groudon and Kyogre other battle-only super modes with different designs AND explains after gen 6 we play in a timeline where the Kalos war happened and humanity discovered megaevolution, explaining why we never heard of the phenomenon before
>SM introduces a super nuke stuff that always existed but we never heard about until now, but also keeps megas around, then USUM adds the ultimate version of the nukes, Ultra Burst... a battle-only super mode with a different design, like a mega (same BST increase even)
>Let's Go removes the nukes but keeps megas again
>SwSh removes megas and adds an inflation fetish shit that also existed since forever but we never heard about, with the superior version being... a battle-only super mode with a different design. The mascots also have their own battle-only super mode with a different design, like megas (same BST increase again). Oh and the third legendary also has a battle-only super mode with a different design
>Legends is a new game that stays gimmickless for once
>SV removes inflationshit and has a mechanically interesting gimmick BUT the peak version for the third legendary is battle-only super mode with a different design, again like a mega (and again with the same BST increase)
Let's be honest, keeping megas would have been the objectively best option here. No random super powers that were always there but we never heard of in previous games (because different timeline), no countless gimmicks that have to be added and removed every gen, no powercreeped super modes like double HP mons with four nukes, etc.