I am not a fan of how awkwardly most designers insist on writing things like moves. “To do it, do it” is the least helpful bit of text imaginable. Switching to a more traditional presentation of actions would likely get a lot more people to grok these games.
I don't mind "to do it, do it," but it's not clear without further explanation. "To do it, do it" is admittedly much pithier and catchier than "If you want to trigger a move for your character, your character has to do the thing that triggers it."
I will say, however, that a lot more recent PbtA games (and their kin)
IMHO do a much better job at explaining the core game ideas for new players: see Magpie Games, Stonetop, Ironsworn, etc. Some of these games move away from the exact wording or at least bury these ideas in more cogent explanations.
I’m also not really a fan of picking most of your character’s narrative arc at character creation. I prefer those things to be organic rather than a track to follow.
This really depends on the game of PbtA. With some PbtA games, yeah you are picking your character's arc. I agree. I generally dislike this since that can feel a bit too prescriptive.
I am also not a fan of how setting specific some playbooks can be. In some games, you are not picking somthing like a Warrior with the playbook, but, instead, the closest thing to a warrior may be the Toxic Trash Avenger of St. Mitch playbook. I understand that this leans heavily into the setting and a boon for some, but it can be a line too far for me. It really depends. Thankfully for me this is definitely not universal among PbtA games.
I found the games notably harder to hack than traditional games, since you need to make sure that any new move fits with the existing ones and doesn't break the flow
I definitely agree with this, but I also understand that this may be a personal thing. There are clearly plenty of people out there who are hacking the game to create new PbtA games or new playbooks. However, I have had some difficulty with coming up with new playbooks for different archetypes for Dungeon World or even Stonetop (e.g., an Iron Age magical artificer/smith). So I have personally chalked this up to shortcomings in my own personal understandings of the game and put some of those hacking efforts on temporary hiatus until my grasp of the game improves at the design level.