Let me start by saying that if there's another thread about this i will delete mine and repost this in the comments there.
So, Senna when she reaches the first range upgrade and buys her first full item passes from being a nuisance to full god mode. Her healing, both from lifesteal and q, is crazy. This reaches the point where a Quinn with 1 lifesteal item, boots and 1 leth item can't out damage her healing. If that wasn't enough she also has range for weeeeeeeeks, like man she outheals, outranges almost all ADC's in the game.
This I say with the objective that RIOT takes into consideration nerfing her q a lil' bit, so that there's a chance in hell to outplay Senna in 1v1.
Hope y'all don't get mad about this and please comment your opinions about Senna's crazy high healing.