So this is all a flaw of making it completely open world with (basically) no structure, which ensures there's no way to teach gameplay mechanics through good level and enemy encounter design.
"Flaw" is one way of thinking about it but I would say it is a necessity if you want casual players to fully understand and appreciate your game.
If the unlocks happened at set story points, I would agree with you. Then, you can unlock a move right before a sequence where the player will need to use it, so that they will understand when the move is helpful, and the designers can ensure its mastery.
The problem with XP is that it doesn't work like that. The designers don't know what skills I will unlock at what points in the story, so they can't plan for them in their level design.
That logic works if the game was completely linear. Since it's open world, assuming there are side missions of varying difficulties all over the place, the game has to allow players to learn skills that the player thinks is necessary or important for them.