How to refine URF to be a permanent mode

I don't think LoL will keep URF permanently if they keep having to ban champions every time more OP combos are found. So, I have devised some example rule changes for URF mode that might make it viable for all champions, but still fast-paced and fun:

1. Instead of 80% CDR, there is a sliding CDR reduction as the game progresses. It starts out at 20% CDR, then champs gain 1.75% more CDR everytime they gain a level, to a maximum of 50% CDR at level 18. This does two things: It allows for items and masteries with CDR to not lose value until mid-level, since it will take 11 more levels to hit 40% CDR, and it caps CDR at 50%, which will not result in as many infinite combos and really broken scenarios. This change will affect both summoner skills and champion abilities.

2. Give champions bonus health regen instead of bonus mana regen. I don't know what the ratio exactly would be, but basically if a champion has items that grant bonus mana regen, it should help with their health regen instead. This is to keep item benefits in-line with their costs. This will only affect champions with mana.

3. Similarly to bonus health regen, give bonus mana some kind of ratio to health. Maybe 50% bonus mana-as-health. That way, items like Rod of Ages are still useful for mana users without feeling like they are losing 1/3 of the stats. This will only affect champions with mana.

4. Reduce or eliminate health costs for champions with health-cost skills. If need be, those champions can receive some kind of nerf to life steal to compensate. Maybe the first 5% of their life steal is ignored or they have a 10% penalty or something. Overall, though, I don't think it is fair that life champs can effectively kill themselves now.

That is all I have right now, but I think that these changes would keep the game fast-paced without creating some of the really ridiculous situations that exist right now.

this is a semi-repost because the old post was eaten by a grue