I get what you're saying, but considering Winks and SIssoko, I´d say only Winks is a good midfielder in terms of positioning. Sissoko doesn't get credit for other aspects of his game, I agree, but being positionally good is not one of them - at least not as a number 6/part of a double pivot.Yeah, that's what I meant by my comment. He gets stuck into tackles and breaks up play.
Winks and Sissoko are both positionally pretty good defensive players (both don't get enough credit for it), but neither is a natural tackler.
In my opinion, he can be good defensively playing on the right of a midfield diamond, or as a defensive RW.