Aight.
Typically I don't see people whining about these specific champs (except maybe kayn and ornn for the reasons you mentioned), and personally I don't see issues with any, so here is what I think your issue is:
Most of the people you mentioned have strong ganks when their gankees are overextended. Thus, I'm guessing ur just ass as watching your back, and always go aggro in lane. So, I would suggest either learning to be more passive, purchasing red wards/warding in general, and watching the map.
In terms of champions, I would suggest people with more running-away potential (
), or with a good resistance to ganks (
). Alternatively, you could try playing the ones you think are OP, and watch how people deal with them. I know that after playing Kayn and Rengar, I knew what they wanted and it was a lot easier to counter them.
Hope this helps