Players are always getting faster. McDavid is faster than Orr was 50 years ago, and someone will be faster again in another 50 years, probably long before that. There's more to skating than speed though, Marner for example is an excellent skater despite being slow. But sure McDavid is awesome, not just super fast but also right up there with the best stickhandlers of all time like Perrault, Jagr, Lemieux, Kane, Orr, could list a bunch of guys here really.
I would say that McDavid is not just fastest, but the best overall skater in the league. I don't know who's second best, but I would say that the gap between McDavid and whoever you have at second is much smaller than the gap between Bobby Orr and anyone else. Orr was unreal, he used to skate backward at practice than anyone else could skate going forward. He also had elite hockey sense, on a level with Gretzky. He was so far ahead of his time and a good an example of what's meant by the expression "a man playing with boys". Bobby Orr did things nobody had ever done before, IMO he is still the best skater ever and he changed the way the game was played.
Just curious, did you ever see Bobby Orr play?