I agree, ARAM URF is not a suitable replacement. I get that certain champions make the game a lot less fun because they ALWAYS show up. Champions like Zed, and such. Though You have the option to ban champions now TEN champions over the previous eight. Banning the broken champions shouldn't be an issue.
For me part of the fun was like "I can't wait to see how broken my favorite champion is"
or
The fact that some champions that are useless in the dictated relentlessly meta that you'd normally get flamed for even buying are actually at least possible now.
Making it ARAM optional isn't a thing because everyone knows if it was ARAM or Normal Urf NO ONE would be playing ARAM urf. or at worst No one would play either because the Queue would be split into two which would make game finding so much harder.
In my opinion they could at least make it Annually to me making URF ARAM is like Halloween but you can't choose the costume you wear because everyone wants to be a power ranger.