Not too sure what to think of Markov yet.
My guess is that he just hasn't reached his peak condition yet, and by this i mean the physical and neurological timing of everything he has to do, and do it at an elite level.
In the past two years, his body and especially his mind, have gotten used to rest, rehab and a whole lot of training. It just can't come back and be at the same peak from the get-go. His mind also has to get used to the cues once more, all the little details that lead to action-reaction.
It's been what now? 13 games last year, and back then he was trying to find his overall synch, 22 games in the KHL and 33 games in the NHL this season. And people are expecting him to play at an elite level defensively?
So far, considering that he actually needs to get back to that level, it looks good with what he has shown, and I think he can only get better and probabilities are that he will.
Also, the problem with his foot speed might be due, not to a 'bad' knee, but rather a knee that isn't used to doing the things it needs to do, especially his new ligament, which is also central to how his leg reacts.