If anything, ARURF is worse than normal URF
I'll be honest here, I am one of the people that wanted ARURF to be a thing. It sounded like such a good idea.
What I forgot was that ARAM had a lot of problems too.
There are a lot of ARAM games that are won in champ select. If you have a lux, soraka, and sona on your team then you've already won. This is multiplied on ARURF because if they have a team composition that counters you, they can opress you to the point where you can't even stay under tower because they can turret dive at 3 minutes into the game.
You can't help but let your enemy snowball in URF, leading to games where comebacks are VERY, VERY rare. Even if one of your people is fed, the probability of their team having enough CC to lock them down and kill them is so high that it won't even matter if they're fed or not.
Maybe this is just a rant for me (In all honesty, it probably is), but I think that ARURF takes all the problems of ARAM and multiplies them by 3.
At least in normal URF you could pick someone that might be able to go against the Lux/Xerath combo. IN ARURF, you just kinda lose because they gave you Pantheon.