I think the consistent criticism of Kolarov is fricken ridiculous on a couple of levels. First, it's quite clear most of our players are too nice and we need someone with a bit of cnut about them, and second on a pure ability level, he's way ahead of just about any other leftback around, including Clichy.
It wasn't so long ago I used to read the 'experts' on here extolling the virtues of Taiwo & Moreno and others if similar ilk. Not a one of them is even close to being as good as Aleks.
He's also obviously a respected squad member off the field too, so replacing him would be a big risk from that viewpoint.