U.R.F. mode, or Ultra Rapid Fire Mode has always been the fan-favorite game mode. The addition of the weekend rotating game modes hyped up the League of Legends fanbase, until we realized that URF wouldn't be included in the usual rotation. It would remain at it's April Fool's Day position, and even some years it was taken out for Draven Mode. Anyone looking at the comments of the announcement on the League of Legends website could see the fans wanted U.R.F. mode. Making URF mode permanent might decrease the popularity of normal and ranked games for a while, but it would also bring in a lot of new players, if they heard "There's now a game mode in LOL where you don't have mana costs and 80% CDR (Cooldown Reduction)!"

The positives of Permanent URF:

Happy fans, more players, quicker queues for the mode

Riot Games should bring back URF mode and make it stay PERMANENTLY.