Ok well my experience with arurf is getting one of the many champions that dont have good cc or decent mobility or damage for that matter full of a team of similar situation types due to the all random part against a team full of long range easy spam kill shots that are zipping around the map killing everyone leading to camping my teams fountain. In fact I played it nonstop when it came up and the amount of games that were complete trash and unfun due to the shit matchup way out weighed the games where my team was at least on par and we got champs that were fun to play in the mode.
Like the reason you see a lot of the same champions in the default version is 1. they don't give a lot of bans and 2. those champs are both fun and exciting to play in the mode where as getting teric who can only stun a bit and do literally no damage against your will then fighting a team of long range mages and assassins was a ton of fun let me tell you. And the reroll system in it is trash, it needs one that gives you 2 rerolls per game not the same ones aram uses because there are a ton of champs that are literally no fun and unlike aram where if built right at least they can benefit the team to a win, in a mode where damaging abilities are flying constantly and being super tanky is all but worthless without dps to follow it up alone it's just not fun...in a mode built around silly antics and stupid combos forcing the players to not have fun because people wanna play the fun champs and that doesn't give variety so they cant all have fun while playing it.
Like have you ever gotten Sol in the mode? it fucking sucks ass because he's not someone that spams moves ever you have to float near a person while they bombard you with attacks. Like all you do is give each person on each team a ban, 10 bans total, you'll still get variety but people will actually have more fun, hell even make it normal draft with 10 bans, then there's more risk to letting a champ through because both teams wont get the op person.
Aram is the way it is because sure you can get unfair matches but I've been in tons of losing matches of aram where my team managed to hold on and push through till late game where our champs florished and we won. Like sure there are team stomps, it happens in all modes but aram you do have a chance to come back with a lot of the comps that get put out there. But in urf where its not a matter of getting to late game because its over before then, the team with the harder damage and cc will win before any comeback can happen. All that matters early is heavy cc and damage and being forced to go someone who can't do those things into a matchup of people who can is so rage inducing it made my entire group not want to play arurf because for 5 games straight or so we got shit champs for it against good teams for it with super limited rerolls so you're stuck with shit. Like leave it to riot to make their most fun gamemode unfun more than half the time.