As far as the Fairy type goes, the only things I agree with are its immunity to Dragon and strength against Dragon and Fighting. It did not need to have a total advantage over Dark, which has never been one of better types both defensively and offensively, nor did Bug need another type that resists it.
On top of this, Azumarill and Togekiss are currently the only Fairy types who are strong enough to have much of a chance against Dragon types, due to having both the defenses and attack to go toe to toe with them. All of the others are too frail to stand up to them, and crumble quickly even to non-STAB/SE attacks. Annoyingly, the dragon who got hit the hardest was Hydreigon, who was already the least popular of the pseudo legendary dragons due to its lack of stat boosting moves and subpar speed stat, and now it's virtually hopeless against Fairy types (As well anything faster then it that knows Dazzling Gleam) unless it predicts a switch-in with Flash Cannon, as almost all Fairy types have too much special defense for it to OHKO.
Steel losing its resistance to Dark was nice, but not nearly enough to compensate for what Fairy did to Dark, and Ghost is now flat out better then Dark both offensively and defensively on top of having the additional benefit of being immune to trapping effects.
Mega Evolution made a number of already good Pokemon (Namely, Lucario, Gengar, and Blaziken) even better, while failing to make most of the weaker ones strong enough be worth consideration over them.
Very few Pokemon outside the ones who gained the Fairy type or a Mega Evolution got any meaningful changes to their movesets, and even some of the ones that did got shafted (IE, Manectric, who has both the lowest overall stats out of any Mega on top of still having gained virtually nothing since gen 4 moveset wise).
I'm really not expecting this game's competitive balance to be any better then the previous gens overall. The only thing I do like at this point is the nerf to weather abilities, Grass' immunity to powder moves, and Electric's immunity to paralysis.