Okay Riot, I don't care how hard it is to do, just do it
Every time I hear someone say it can't be done, I think "Certainly not by you; you have admitted you aren't smart enough to do it." What I'm talking about is balance all champions not only for ranked and the rift, but for Howling Abyss as well.
Yes, it will be way more difficult that what you have done so far. It will mean that any champion that has insane amounts of damage will by necessity have to be easy to kill. It will mean that tanks/brusers will have to choose between damage and survival. But that is doable.
It will mean that champions that are way op need to be nerfed. It does NOT mean that any champion needs to be buffed (you can balance all by nerfing). In fact, I'd recommend riot that you refrain from balance by buff for the next 4 seasons ... do all your balancing by nerfing the rest of the champions if need be.
You can start by putting real cd times on all champions and removing all reset of timers for all champions (really? you have a cd of 0.1 seconds on yas? ... get real ... with a 40% cdr, that goes to 0.06 seconds ... NORMAL internet latency times are on that order of magnitude, which means it is zero cd).
It doesn't work. Nor is it balanced on H.A. and you have to balance all maps, not just the one that ranked uses.
Riot, GET REAL! if you really are too stupid to accomplish it, release the source for the open source community to make it happen.