I think I know why the game seems stale.

This is just potential and opinion, though it certainly feels like the right reason. The game's multiplayer feels stale because every fight is the same, it's always sidestep, start back attacks, infinite chain until super counter, repeat, with the occasional break in combo. It just seems pointless because if you can't super counter (which was nerfed to all hell) you can't get out of these infinite combos. Making the game repetitive and unfun to play online.