Yeah but Mecir just lacked the top end speed of the elite scramblers and didn't have elite offensive footwork either, that wasn't really his game. Anyways, I just don't think you can leave Nadal out, all things considered he's likely the GOAT mover considering the longevity at which he did (and still does) move at an elite level and his unparalleled combo of physicality (I think those impossible gets can have a big psychological effect on the opponent, unlike other guys who could also cover a ton of court), footwork, and court coverage. Sampras is up there too but I guess his movement fell off a bit too quickly, but at his peak he was up there with anyone (incredible offensive footwork and serve and volley footwork and awesome speed). Federer's quick lateral movements are a bit better than Sampras' (and anyone else) but Sampras was a little faster/more explosive and had better S&V footwork, although Federer sort of stopped practicing it. Relative to his era, he was probably close to as good a mover as Federer at their respective peaks.
In terms of elite movers post open era, I think the list is Nadal, Borg, Federer, Djokovic, Sampras, Murray, Hewitt, and Chang (who is truly underrated as a mover, the dude was just phenomenal). Mecir is probably just behind those guys.
I think we maybe just have a slightly different idea on what great tennis movement is. I tend to think mind is as important as body, if I can put it that way. Anyways, Nadal is a good choice too, even though I don't think his footwork is among the best of the best, simply not as refined as Federer's, Connors', Mecir's, Rosewall's.
As for Mecir, he had more than enough foot speed, he just(again a bit like Federer) did not sprint as much as the other great movers, simply because he didn't need to, he was kind of always there, well positioned. Great sense of court has a lot to do with it, also ability to predict the opponents next move and the other things I have mentioned in my previous post. He was similar to Hingis on the women's side here. It was how they used the court sort a speak(plus elite footwork) that helped them to always be in position. Also his movement forward is very overlooked. He was known for his great lateral movement back then, especially in contrast to the net rushers of his time, but he was actually very good moving forward. You can find most of what I am talking about in this short clip, one point only - coordination, footwork, foot speed/sprinting at one point, moving forward...:
We can give Nadal an advantage for his fitness of course, but then again I don't know if any player from Mecir's era or before him could keep up with today's field in that department, except for Borg. The level is completely different now.
I would agree that Federer has the edge over Sampras when it comes to lateral movement(Borg is still the best for me there), and the other way around for moving forward. Both amazing movers, Sampras was more athletic, Federer had more finesse in his movement, if I can say it like that.
All in all, my list with my criteria would go like this: Borg(both phenomenal athlete and disciplined footwork, coordination), Mecir, Federer, Nadal, Laver, Chang(don't think he is underrated though, his mobility is what he is known best for), Rios, Sampras, Rosewall, Edberg, Hewitt, Djokovic, Murray. More less that order, and I must have forgotten someone. More recently Simon is great.
