There was wild speculation about what the Pokemon Company wanted to do with Megas in Gen VII, mostly because in the many reveals we have gotten so far, they were pretty much a no show. Finally they got confirmed (and excluded from VGC 2017) in the last batch of reveals, but the fact remains that no new Megas have been introduced in the new games. Which is expected considered that Megas are so cool and so mean that they would steal the thunder from brand new mechanics! In order to be hyped about this games it’s better to look beyond Mega-Evolutions.
This is also something to consider from a gameplay standpoint: Megas succeeded where previous gimmicks failed. Gen IV games gave us new evolutions for old Pokemon, making a handful of the old cast look dated in comparison. Megas don’t have the same direct impact on their regular counterparts, as they can be different in abilities/typing and have their use limited in a single team. But the limitations were pretty glaring too: Megas by definition only affect a handful of Pokemon, they are a restricted mechanic that was applied to fan favorites and final evolutions. They don’t upgrade full evolutionary lines and are prone to power-creeping the game: just a handful of the existing megas can perform a proper support role and in most cases you are just better off using a Mega Salamence smashing enemies with powerful attacks.
So the two main Gen VII mechanics that look to upgrade the existing Pokemon cast went their way to avoid the limitations of Mega-Evolution. Regional variants can effectively affect non-fully evolved pokemon and can perform support roles better than a pokemon competing for a Mega slot could. Z-Moves have generic forms that can be used in about any Pokemon in the game, no longer restricting the power of Megas into a short list of fan favorites (effectively updating the versatility of all the cast!). Also, signature-Z-Moves are proposed as an alternative to good ‘ol Mega Forms: they are a way of giving a competitive pull to targeted pokemon without inflating the Form Pokedex. These options do not aim to replace what Mega Evolutions are meant to convey, they are more of a way to fill the gaps left by the mechanical choices that made Megas happen.
A third very welcomed mechanic is that of Totem Pokemon, which are essentially boss matches that do not follow the straight power curve that Legendary and Mega pokemon have (as they have to become playable and relate to the existing status equations). They are given the unique quality of summoning enemies to their ranks, bringing a challenge that is as much about versatility as it is about straight power. It’s going to be more of a background change compared with the two we discussed above, because it’s not something you play with instead you fight against it. Hordes also broke the regular symetry of Pokemon battles and are one of the mechanics I really found succesful in Gen VI, so my I’m optimistic about Totem Pokemon being employed like this.
Breaking the straight line of battle power is a good thing. But you also need to test the limits of power you can have! Which is also the line of thinking that we’ll explore next when we get into depth about Z-Moves.