URF and ARURF both get stale after a few games regardless of whether or not you get to pick
In URF;
There are maybe fifteen to twenty champs you'll see at least three of in every game who are IMPOSSIBLE to play against, because of tier-whoring people who don't know how to have fun. I'm talking Sona, Jhin, Teemo, Maokai(Who's probably worse now with his new sapling toss} Shaco, Ryze, Riven, Pantheon, Wukong, Karthus, AP Nasus, Blitz and Ali together(probably worse now than Ali got a stun too), etc.
A shit load of champions that are barely played because one or two people actually say "Hey, maybe 'X' champion would be fun to play in URF!" Only to get fucked by permastealth Wukong.
A bunch of champions that are completely unplayable garbage because CDR isn't that great on them. Champions like Yasuo, Aatrox, and most adcs.
ARURF didn't make this much better because the "RNG" picked mostly the same champions every game, and if your team got a shit tier like Yasuo, or the enemy got a god tier like Karthus, you were fucked.
Hexakill and One For All are great though