Why did we drop the Strong/Agile style attacks and the actual turn order that made speed matter more than in the opening turn?

That whole system was so bad though, where moves all had hidden initiative costs and the whole thing was extremely obtuse and inconsistent because it only mattered when they hit the threshold to give a second consecutive turn to one pokemon or the other which also wouldn't line up with the displayed order since your opponent could just do a cheaper move and attack twice or stop you from attacking twice anyways. And then there was whatever they did to the damage calculations to make everything way deadlier and flatter across the board in unintuitive ways. How weird, inconsistent, and spiky the battles were in Arceus was the absolute worst part of it.

The world was a decent first stab at making an open world game, but all the mechanical changes to the core gameplay were just bad.

Not that it really mattered, since almost all the battles were against wild pokemon and all the big fights were just the player running around throwing shit at a darksouls-lite boss instead of using pokemon. I never even finished it because it got so boring and felt so pointless. It was just not a fun game at all after the novelty of the open world with pokemon wandering around wore off.