Galchenyuk OR Stone?
Galchenyuk OR Monahan?
Galchenyuk OR Johansen?
High draft pick being developed at a snails pace to make room for local boy OR the Player who has been allowed to play in his preferred position and flourish as a consequence?
Monahan has the same amount of ES goals as Galchenyuk in 15. Despite being deployed as his team's #1 centre. He's being killed possession wise and will hit a wall sooner or later. He'll likely have a pretty bad sophomore slump next year. 30 goals is nothing to scoff at for a 19-20 year old, but half of his goals are PP goals. Give Galchenyuk a decent PP and he'd likely have 30 goals as well.
Stone is killing it this year, and his underlying stats justify it. He's playing great hockey. He is however a year and a half older than Galchenyuk. Talent wise, he isn't all that close to Galch. He's physically stronger and plays with better linemates. Individually, Galchenyuk has created more scoring chances. Relative to his teammates, Galchenyuk has been a better possession player than Stone. Not to take anything away from Stone, he's a heck of a player especially for a 6th rounder. Once Galch finds his groove at the centre ice position with top linemates, he'll be a step ahead of Stone. Also, I doubt Stone's 16% ES shooting percentage is maintainable.
Johansen is a heck of a player, but again his underlying stats don't justify his comparisons to Galchenyuk. At ES, he has a grand total of 1 more assist (15g, 18a vs 15g, 17a for Chucky), despite being older and playing top line minutes. His goals per 60 and his points per 60 are lower than Galchenyuk. Possession wise, he doesn't hold a candle to Galchenyuk. Relative to his teammates, Galchenyuk has been significantly better possession wise and has also created more individual scoring chances. This despite playing out of position. I love the player, but Ryjo tends to get overrated because of his physical / feisty side.
The only one who really compares to Galchenyuk is Stone. He's playing out of his mind and argument can be made that he's the best of the 4 players you mentioned at this point in time. However, going forward Galchenyuk is still the most skilled of the bunch and has the highest ceiling offensively.