I think some people also don't know Marner's game yet. He's never been as flashy as Nylander and I don't think he ever will be. Nylander plays more of a big ice style, with more skating with the puck to stretch the defense and open up seams. Whereas Marner plays in traffic a bit more and is a bit more about making quick passes and reading where the puck is going to go. The 3rd game was a good example, Nylander looked more dominant but it was Marner who put up the two points by being a couple steps ahead of the defense. Could be one of those guys who's around the puck a lot but doesn't seem dominant, and then after the game you look at the scoresheet and he was involved in 3-4 goals.
This is one of the few times I actually really agree with you
Although Marner is more of a flashy player than you give him credit for. Also, its the casual fans that don't notice Marner; real fans will notice how good he's been in a game and how flashy he really is. Look at rookie game #3, Marner got 2 points and was the 2nd star, yet all the talk was about Nylander's dirty goal when in reality Marner was a much better player that game and even had some nifty passes/dangles.
I think the fact that Nylander dominated the rookie camp the way he did raised our expectations of Marner, since a lot of people(not just fans on his board), did ranked Marner higher than Nylander before this camp. When Nylander played the way he did and Marner was not even close, it was disappointment.
Truth is, Marner might not played as well as Nylander, but he did alright.
As for Willie, from all the rookie games I watched so far, he is at another level and even better than McDavid. But it was such a small sample size of games.
I was at the 3rd rookie tourney game against the Pens and Marner was definitely better than Nylander.
Should also note that Marner is a class act as he came out to talk to a fan with a disability (as well as the other ~15 people that had stayed for 45 mins after the game) despite the fact that he was going out for dinner with his family. Other players did as well (such as Nylander), but mostly because they were using that exit whereas Marner did just because he heard the guy was waiting. Even told the rest of the people that he would sign autographs/do pictures in a few minutes, but wanted to talk to that fan first. Really glad we picked a guy that seems as genuine and nice as he does as well as ridiculously talented.
Edit: Also, the fact that you say he is on another level than McDavid is absolutely ridiculous... Even with the extra year of development that Nylander has, McDavid is currently a much better player and obviously in the future the difference will be night and day.