Some love for underpreforming ADCs?

Right now I feel like most ADCs are in a good spot, but there are a few that just can't keep up with the others. In particular I mean Varus, Corki, and especially Kalista. All three have pretty bad winrates around the board, they don't do as well as other adcs, and they don't feel as satisfying as playing other adcs.

I feel like riot needs to just give these champs either a buff to push them in the right direction, or a complete overhaul to make them easier to balance (Kalista)