You get a random card after each fight. Card choices are now an optional fight reward you can route for, just like healing or gold (in such cases you get both a random card and a card choice). It increases randomness a bit at the beginning but you just collect more cards overall so you can cycle out basics faster and select which cards to keep. If you want more agency you can still route for card choices and shops.
Cool idea in theory, but terrible with some characters in practice. I tried playing Amber on Maze power 2 right away, and my experience was absolutely miserable. In the previous update, at least with Ruby, at equivalent upgrade, I easily reached floor 3 on my first run. With Amber ? I got destroyed on floor 2 in two run, and not because I felt I played poorly, but because I literally didn't have the tools to survive. The main reason for that is, as of now, Amber is by far the weakest character, and really need a buff. She can't reliably kill or defend quickly enemies like Ruby does, doesn't have the draw power and the ability to tank reliably like Pearl, and can't reliably generate mana and useful passive effects like Beryl. Her cards at 2 mana costs are borderline unplayable starting floor 2, because they take nearly your whole turn, and don't accomplish nearly enough for the cost. Her 3 mana cards ? You'll take 50-75 dmg if you played them. You desperately need some specific cards with her to barely have a chance to survive to begin with, which was possible previously, but you basically can't do that anymore, because if you don't go for the cards, you're screwed, if you go for it and don't get the good ones, you're screwed, and even if you go for it, and get the cards you need? If you didn't start with card upgrade rank 4 and starting lvl rank 4, you just put yourself behind in the exp and gold curve and now you don't have the resources to go for shops anymore, or have a high enough passive. I will go and farm shards on Maze power 1, because I'm forced too, so not really fun, and then I'll try some new runs and see what I'll get..
Balance between characters isn't perfect yet, it's an iterative process, but I am trying to make sure every character at least feels right against the current content. I am quite confident about Amber's power level, and she currently acts as the benchmark across the cast. She can get quite technical despite her apparent simplicity. I am aware Maze Power 2 can be rough, though, and will continue testing to make sure every character feels powerful in their own way and gets a fair chance.