Why didn't Riot keep the same champions banned as they did last year for URF?

Despite the changes, a lot of champions that became a problem in URF (like Nidalee, who's received no changes), are unsurprisingly still causing chaos on the rift.

Even with 6 bans in total, it's not enough to stop the ridiculousness people are doing just so they can stomp the enemy team and win in about 10-15 minutes.

I know this is supposed to be a fun game mode, but it's not fun if one side is purely choosing champions to get a win.