I hear you, Oedo. I realize that rant was... a little over the top, but something about gen 6 really soured me and it felt like a step back from what i feel were the best games in the series.
basically, the only other changes to the type chart that happened in X and Y besides the inmplications of introducing the fairy type and making that Poison and Steel weak, Steel lost it's resists to Dark and Ghost. Granted, Steel resists a laundry list of other types as is and fairy was added to this group of resists, and even without dark and ghost resists, it's one of the best defensive types.
Ghost now has dark that resists it in the wake of steel resist no longer being a thing, and the normal immunity. that's it.
the thing I was talking about with Ice defensively, is that Ice resists... Ice. it is weak to Fighting, Fire, Rock(!!!), and Steel. the problem with ice type is that it's fairly obvious that it was originally conceptualized as a compliment to water types to trade off some of their resists for a better offensive option, but as the game has evolved, Ice has easily been the most stagnant type. Sure, there are great ice moves and Gamefreak has VERY gradually given them support in the form of Hail (without getting into specifics, look forward to some more limp-wristed attempts to do this that I've heard about.), but it's just not good enough. most pokemon that are ice types are poorer for being ice type. unless you're wicked fast (Weavile) or hit like a truck and pack Ice Shard in your move pool (mamoswine), or you have some dumb gimmick (Cloyster, Walrien), being an Ice type is a bane and not a boon...
(also, the reason being weak to rock is devastating is because when you are weak to rock, you take a quarter of your max HP coming in on stealth rock instead of 1/8th. if you're x4 weak to Stealth Rocks, you take half coming in.)
Mega Evolutions... I feel restricted team building. a lot of them I actually like. they were targeted at pokemon who were popular, and my favorite megas were the ones tartgeted at pokemon that needed that little extra something to shine or the ones where you actually were giving up something when you mega evolve (Garchomp losing speed when it become Garchomp-M, Slowbro dropping an amazing ability in Regenerator to gain extra defenses.) and... quite a few megas pretty much lived or died on a gimmick, and some of those gimmicks would make for a stupidly busted pokemon. I mean, on one hand you are giving up your hold item slot, but it's usually the pokemon that are just made straight up better than any hold item could ahve provided that pokemon that ended up breaking the game like Salamence, Pinsir, Mawile, Lucario, Blaziken, Gengar, and... of course, Mega Kangaskhan, which they specifically released a Japanese Sun and Moon trailer to point out that they rebalanced because they messed up so badly in designing that singular pokemon.
The real sin though is that it took them exactly one game to break the one rule they established with Mega Evolution; that the mega evolving pokemon needs a hold item. although this doesn't really effect most of the main game, Mega Rayquaza doens't need a hld item. it gets the highest base stat total of any pokemon. All you need to mega evolve it is for it to know it's signature move, which is a flying type version of Close Combat, AKA the best fighting type move overall. Mega Rayquaza is a flying type without flying type weaknesses, but sure as heck still has flying type resistances and Same Type Attack Bonus. Mega Rayquaza hits like an ICBM weather it's using physical or special attack. Mega Rayquaza can use Life orb. Mega Rayquaza can use swords dance or dragon dance. Mega Rayquaza gets access to extreme speed, which is a normal type attack that hits hard, and outspeeds most other priority moves. it also happens to have pretty great defenses. and... let me reiterate; IT CAN HOLD A HOLD ITEM! ANY HOLD ITEM!
Mega Rayquaza is such a busted pokemon that the fine folk over at smogon university declared that for their self-imposed competitive balanced format that you cannot play Mega Rayquaza even in the banned tier, uber usage. no single pokemon can take two unresisted hits from mega rayquaza and live. the only reason it didn't dominate the VGC tournaments (and let's face it, it kinda did) was because Primal Groudon and Primal Kyogre's attacks hit both of the opponent's pokemon stupidly hard instead of just one of them.
that's where i get to Z-moves. is is something that doesn't favor just a select few pokemon. There's probably going to be balance issues with folks ddoing Z-move explosion given that the Z-move scales with the power of attacks (proven by the demo if you catch a pikachu in the catching mini game and give it your electrium Z Vs. the attacks that Kukui's Pikachu had), it probably means a lot of the use cases for Z-moves are either one-and dones to take out a single big threat on the opponent's team, or that there's (maybe) support moves like Extreme Evoboost that set up sweeps, which... passing stat boosts are already things the game has counters built in for, like whirlwind, Roar, and Haze. at the same time, it still gives effectively the same thing for the single player adventure of giving one of the pokemon on your team a chance to shine, even if it's normally not a super great pokemon.
Also, Rygar... did you enjoy that Greninja I sent your way? :3