Connor has great skating ability and a very advanced skill set, but he needs to make numerous adjustments to his game in order to be more effective than he is now. Both his playmaking and scoring ability suffer because of some of his current tendencies. One of his problems so far is that he doesn't keep his head up when he makes plays. Often, he'll blindly throw the puck into an area where none of his teammates are; while he has great passing ability and can make crisp passes, I think he overestimates his vision. From what I recall, Jason Spezza used to also have this issue of "passing into an area" while just expecting someone to be there. The NHL game is far more structured than the junior game, so players are going to be in a certain place based on how they have been coached. Connor will need to learn his team's system in order to make effective blind passes. He doesn't have eyes on the back of his head, as some observers would like to believe. Keeping his head up as he skates and looking around, assessing the situation so that he can make good passes, is what he should do if he wants to make the best use of his passing ability.
Another problem with Connor's game so far is his lack of confidence to shoot the puck. From what I have seen of him, and based on reports from last year, one of his weakest attributes is his shooting ability. He does not take shots from afar. As a result, most of his goals have relied on his hands and his ability to generate a partial break or a full breakaway and then deke the goaltender before sliding the puck along the ice into the net. Goaltenders in the NHL don't get fooled out of position as easily as junior goalies. Throughout the preseason, Connor has had some chances to score, but each time he has simply driven the puck to the net and then stickhandled the puck into the goalie. His best chance on Jacob Markstrom last night would have gone in against a junior goaltender, but Markstrom simply covered the bottom of the net and held his ground. Connor needs to adapt his offense.
One on one, he isn't able to beat NHL level defensemen yet. I don't think anybody here expected that he could skate around NHL defensemen with ease. Defensemen have been keeping him to the outside thus far, and some have stood him up. There have been a few times when he has dashed through the neutral zone with great speed, only to lose the puck a few feet into the offensive zone with both defensemen still in proper position.
He is dangerous around the net, though, because of his quick passing ability. When he is in front of the net, he is able to make quick passes through the crease. A few times, I have seen him grab a loose puck at the net, and instead of shooting it he'll throw it to a streaking teammate on the other side of the net. That seems to be something that works for him right now.
He has things to learn. I don't think he will jump in and be able to single-handedly change anything for his club. It's difficult to imagine him lighting up the league in his first year. It will take time before he reaches his peak, unless he is too entrenched in his current tendencies to change. He may eventually be a great player, but he isn't the type of player who will step in right away and takes the crown away from anybody.
He isn't able to do what he wants to do with the puck yet. To be honest, I don't think he is at the level that Sidney Crosby and Alex Ovechkin were at in their rookie year. I suppose many were expecting him to have such a season. I think he will gradually learn to be a very dangerous player with the puck, but he's quite raw right now. I would put a question mark beside the label of "generational player" right now because his development could go in a number of different directions. If he stagnates, then he's in trouble. If he improves, then there are things to look forward to.
He won't jump in and be a dominant player right away. He isn't that kind of player.