Once again, do something about Shiny cards. They are the worst addition to the sets by far. Too many that basically "waste" a good pull, because they're not playable cards and they don't even look good. PLANETA is the worst artist and should be actively removed from the game if possible, really. The basic shiny arts are also ugly. The way Baby Pokemon were implemented in set A3 as a random chance of a sixth card is EXACTLY how shinies should be handled, just at lower rates. The amount of purple Nidorinas I've pulled instead of something actually appealing or at the very least new is maddening. I understand the greed of deNa and TPC is driving this gatcha and that making sets impossible to complete without paying is the goal, but the game is so hostile to players through these transparent RNG hoaxes that I wouldn't even spend money if the rest of the game was perfect.
Also there shouldn't be the chance of getting duplicate cards in the same pack, what is that? So not only is it hard to pull anything good, it's also entirely possible to get a pack where you pull three of the exact same awful card! I've seen it happen to myself and in Wonder Picks and it feels like a cosmic punishment for not spending enough money on the game. Actual trading cards don't do this for a reason.
Pack Points are a terrible system that might as well be removed. The actual costs of cards vs how many points you get per pack makes no sense-- why do I need to open TWO HUNDRED FIFTY packs to get a bog standard EX card? At the rate of pack releases, no non-whale will ever get enough points in any one set to redeem for something good (and at that point they should have already gotten every card anyhow). Also why aren't the points shared across packs? Why are the old and useless sets still the same prices?
20 deck boxes is too few in a game with 9 expansions, and decks shouldn't be resetting the energy type every time you go into the menu and change something. Just forcing multi type energy even when it was set to something else is the worst because players forget to fix it, go into a game, and then lose immediately.
Again, too many screens on wonder picks and battle victories. Needs to be sped up or consolidated.
20 card decks are quickly become a disaster in a game that's now solely balanced around draw power. Professor's Research was already broken, Sylveon ex is even more broken, and now the game is basically draw your entire deck in one turn or you lose. It isn't fun when I'm at a 6 card disadvantage just because I bricked.
Also, there is something fishy about the matchmaking forcing you into duels against decks that counter yours, the fact that everyone has a 50% win rate in ranked is proof. Also, some of the bricks that occur are humanly impossible in scope and frequency, it's like the game decides one player will be restricted to bad RNG the entire match just because.
There's no reason we shouldn't be able to use any card art as an avatar.
There's no reason to have trading and wonderpicking restricted to only low rarity cards besides the aforementioned greed. Again, it just serves to make a decent idea unfun to use in reality.
Sneak Peek is the worst event, whenever it comes up the wonder picks that are seen are all terrible and not worth spending stamina on. When I finally do see a good pick, oh wait, no sneak peek! Why is it a random chance, that's literally ridiculous. It should either be guaranteed on all picks during the event or it should be indicated before you get locked into a pick whether or not there's a peek.
The trading wishlist also has no reason to be limited to 20 cards. It is almost useless if every card a player is after can't be listed. The fact that it's only viewable on friends is bad too -- realistically the game should offer something like a Global Trade System from the Pokemon RPGs, where I can publicly put up a card I have for trade and my wishlist can be used as an asking price. But the fact that deNa took 6 months just to replace tokens with shinedust doesn't give me much hope in their ability to program anything useful into the game.
There should be a real deck testing mode against an AI, as the game is, testing decks is terrible because you either have to eat losses in ranked or hope you don't get a concede from an opponent. Just let me play out games against a bot, let me pick the deck it will use. These modes aren't about winning or losing but about seeing if your combo has a realistic chance to work before you try it against a human.

This game had all the potential to be great but it's been wasting it so far, so please actually consider these things for the players who really do care about the game. That I and probably many others have so many criticisms yet keep playing tells you that I don't want to give up on it.