Step 1; ***Don't limit yourself to a small champion pool***. This is the ***number one*** reason that Riot changed URF to the "all random" pick type after it's debut, because just about the whole community basically refused to play anything other than the "most overpowered champions in the mode". If you want Riot to consider classic URF as a viable option over ARURF, you need to get with the program and get involved with champion diversity. If not, Riot will force that champion diversity on you.
Step 2, and this is the most important part; ***DON'T STOP PLAYING LOL THE MOMENT URF IS NO LONGER AVAILABLE!*** This is the biggest thing that Riot has said, and continued to say, about URF as a mode (both Classic and ARURF), and so long as players continue to play LoL ***only*** when URF is available, Riot will continue to hold this over the community as a reason that classic URF doesn't work. Your "protest" has only served as a reason for Riot ***NOT*** to give us more URF (and classic URF in particular) for over 5 years. If you want Riot to even consider classic URF in the future, you need to get with the program and prove that URF isn't the only reason you're playing, even if it's not true.
Step 3; ???
Step 4; ***PROFIT!***
Seriously, if you're making yourself part of the problem, you don't get to complain.