It's ok to balance around high level play
As we all know, riot balanced league around "high level play" and i don't have an issue with this.
But lately, things have gone a little too far.
balancing a champ around "high level play" does NOT mean that that champ should be UNPLAYABLE unless you have the mechanics of high level play.
if a champion is too strong at higher elo's then riot has every right to nerf it. HOWEVER that nerf needs to be done in a way that doesn't completely ruin the champion for lower elos.
there are a few example of this at the moment but i think the biggest one is 
a few patches ago riot said they wanted to lower the clear speed on nidalee and have her take more damage from the clear.
and to do this they removed the root from procing hunted on jungle mobs.
now in higher elos. this had the intended effect.
but the problem here is is LOWER elos. it made it near impossible to play nidalee jungle.
because at higher elos player HAVe the mechanics to kite around the jungle mobs perfectly..
but in LOWER elos.. players dont.
and currently on the pbe see another nerf to nidalee's "jungle"
riot.. i understand that at challenger lvl play nidalee has a 52% win rate
but at bronze play.. she NOW has a 43% win rate, and a 47% win rate in silver it isn't even until high gold that nidalee's win rate reaches 50%
this is BEFORE your PBE nerfs
i do NOT have an issue with nerfing a champion that needs nerfs.
but if you nerf them so much that players below a certain elo cant even PLAY them.. your going about this the wrong way