Pro Bending was a bad idea, not just because it clashes with the time period they are going for, but because it turns what is supposed to be a spiritual form of martial arts, into a really dumb sport where all three elements are treated as simple interchangeable projectiles to be flung wildly at your opponents.
It's just a show constantly marred by the creators having massive ambitions and neither the time, nor the budget, nor the writing chops to follow through on them.
Which leads to them doing irreversibly fucked up shit just to constantly up the stakes, like literally taking forty lashes to the Physical In-Universe Embodiment of the Entire Lore and wiping out all the previous spirits which korra never even got a chance to talk to. To this day I don't have a goddamn clue who seriously thought it was okay to just murder the spirits of the previous heroes onscreen with no fanfare whatsoever.
I agree with the reviews who say it feels like the writers actively hated the original show and cast, despite leaning so heavily on it for worldbuilding and callbacks
Amon will always be the biggest disappointment to me. They only killed him because the studio was so inconsistent about how many episodes they'd be able to have.