I'm saying that Bale having an average day defensively is perfectly fine with me if he gives us a third world class point of attack along with Son and Kane. Let the others in the team do the other work, and let the front three defensive's work be limited to the high, press, backed when need by Sissoko or Lucus, with it primary purpose is to stop quick transitions from City and allow us to reset in a mid block.
Our own transitions needs to be fast, and I personally would be working on blind out balls down the channels and/or based on where City's defenders usually stay when they are squeezing teams, this will help emmensely when we are under the kosh (which we will be). I want son and lucas and Bale to stay high enough to chase these with support thus either preventing City from playing too high a line. Or exposing them to some threat if they do.
All of the above could be outdated shortsighted tactics. As I'm no football manger, but I do manage people, and one thing I have found to be consistent, is that you give the most talented people the best chance to succeed by allowing their strengths to shine and using others to cover their deficiencies.
And Bale may not be the player he once was, but he is still:
1.supremely talented
2.one of our most potent weapons
3.big game player,
4.has a point to prove.
You have to play Bale.