So yes theres the big bug and that is a problem please make that Number 1 fix. However while ARURF is nice to get because it at least is fun in this game that needs some form of fun, there are other things that need changed about it.
Make Zhonyas and GA not get reduced CDR on them seriously just do that no questions or simply disable them pure and simple they are unfun in URF and it should be about fun.
Disable champions Resetting cooldowns, seriously Ezreal, Lucian, Katarina, and a few others that I can't think of off the top of my head, there is a reason that these champs were banned when we had regular URF back in the day they are unfun to play against.
Bring back Fully disabled champions again, Karthus, Sona, Teemo, seriously just do it.
Have a nice day