The common problem of almost all recent broken cards

I was thinking about the best and most broken cards in the games and I believe I have reached a common thread: most of them let you play two cards in one turn. I do not mean this in the same sense as tutors or any sort of card that simply reads something like "play/summon x card from your deck": I refer to cards with an actual body (not the typical 2 power tutor) that are either engines and/or play for more points than their base power.

Fucusya, Artaud, Mammuna (I know it "summons" the other card without Sabbath, but that is generally beneficial), Braathens, Raffard's Vengence (not exactly same turn, but that is not a problem with Inspired Zeal) and, last but not least, Simlas (yes, he himself is "just" a tutor by definition, but the fact that he can tutor more than one card at once puts him on this list). To a lesser extent, I would also argue that Lydia, Fercart, Artorius Vigo and Bride of the Sea are also a bit too good and that they somewhat fit this category, even though they are without a doubt considerably more balanced. (You could also argue that I should include Saskia on this list, but she is a bit different in that she works better the longer the round is. Keep her in mind nevertheless.)

Notice how the vast majority of the cards I mentioned actually came after 9.0. It seems that the developers focused a lot on this "play more than one card on one turn" stuff in Price of Power (even if some are not as broken, which I will mention later). For some reason, their design philosophy seems to have shifted in that direction in PoP and that introduced some auto-include cards: particularly Fucusya, Artaud, Braathens, and Simlas (you won't see any decent SK, NG or ST deck without them). I am not saying that there aren't other broken/auto-include cards that should be reconsidered that don't really do this (the most extreme exemple of this is King of Beggars, arguably the most broken card of the game right now); I am merely saying that part of the lack of balance and variety in the game seems to steam from this common thread.

If we consider other non-tutor cards that play an extra cards in one turn, we can see that many of them (even some of the more recent ones) are relatively balanced.

The first exemple are the Scenarios, which give you two instances where you play an extra card in one turn; they can, however, be answered, even if only with Heatwave, and they are also specific to particular archetypes, and thus can't just fit every deck.

You also have two evolving leader engines that play an additional bronze in one turn: namely Auberon and Harald. But they require Devotion to work as engines, they only do so in round three, and, in Auberon's case in particular, he is even RNG dependent.

Cleaver, Forest Protector and Gerhart can play two cards in one turn, but right now they seem to be decently balanced. Forest Protector and Gerhart are some of the few more "pointslamy" options that ST and NR have, so they play them a lot, but I would still argue that they are decently balanced (again, they just seem to be sort of auto-include because these two factions lack pointslam; which is ok, every faction needs to have its own identity, but sometimes it's good to have something to fall back to in shorter rounds).

Ulrich, Queen Adalia and Ramon are used generally as expensive ways to play a bronze with a bit more defense, and thus I believe they are balanced as well. They are not cheap and they don't just fit every deck, yet they can easily get more than their provisions' worth under the right circumstances.

Then you have what I call "the RNG neutrals": Triss: Telekinesis, Dandelion: Poet and Aguara: True form. They are all way too expensive and way too inconsistent. Triss used to have her uses back in the day, but even then she wasn't really thay good: compare her to cards like Lydia or Bride, for instance. Anyway, that is not exactly a bad thing: a neutral that is too good (cough Heatwave cough Oneiromancy cough) becames too prevalent and hurts deck variety the most.

Then you have the more conditional value cards, like Avallac'h, Artis, Filavandrel, and Fulmar. Avallac'h is somewhat powercrept and he doesn't have much to offer right now; Artis doesn't really have good payoff for what he does and can be easily dealt with; Filavandrel is inconsistent and too dependent on handbuff; Fulmar is without a doubt the most refined and balanced of the four, having decent value on deploy but having way more value come out of his order ability if he sticks, and what he does only synergizes well with his archetype. These three range from mediocre to good, even though two of them came after 9.0.

Finally, there is King Helselt. Let's is face it, he is just the worst tutor in the game: he is supposed to be an engine, but he costs way to much for what he does and is way too limited by what he can do. He is supposed to synergize with Stockpile, but you will most likely use him to get Raffard's Vengence, which needs Inspired Zeal. Overall, the worst case of this "engine that plays a card" deal.

TLDR: Too many of the recent cards have great value by themselves in addition to playing a second card in the same turn and have thus become auto-include.