I'm going with Chmelevski here.
The way I see it, you have Chmelevski, Chekhovich, Blichfeld, Gushchin, and Robins competing here among forwards, with Hatakka and Melnichuk also in the running. Just looking at the forwards for now:
- The odds that any of the five turn into top six forwards are lower, and probably look something like Gushchin, Robins, Blichfeld, Chekhovich, and Chmelevski (with Gushchin and maybe Robins being the only ones with a reasonably sizable chance).
- However, the odds that any of the five turn into bottom six forwards are probably more like Chmelevski, Robins, Blichfeld, Chekhovich, and Gushchin, with a gap between Chmelevski and the other four.
- Chmelevski has scored pretty consistently (using age-adjusted NHLe) as a third-line forward (there was a big drop-off this season from his typical 45 points to 30, but in a very strange season where Chmelevski spent half of the year on the taxi squad), and I think has the skills to play in a fourth-line role as well.
- Robins seems to have clear NHL potential as a scorer, but might not reach top-six quality. With his overall skill set and effort level, though, a bottom-six energy guy seems pretty reasonable.
- Blichfeld and Chekhovich are probably third-line scoring wingers or bust.
- Gushchin is tiny and might not be able to handle a third-line role, particularly as we haven't seen him in a men's league.
- Chmelevski is already a depth forward, I think (NHL 13th forward or AHL callup) - he shouldn't sit in the NHL press box because of his age and remaining upside, but I think he's clearly good enough to fill that role now. Robins might top out there as well. The other three, though, won't - if they can't stick in the NHL, they'll go to Europe and be of zero value to an NHL team.
Basically, I think Chmelevski has very little upside for a top six role, decent upside for a third-line role, good upside for a fourth line role, and is already in an NHL depth role, while Robins follows up with more top six upside and about as much bottom-six upside. Gushchin has better top six upside than anyone left, but pretty much zero chance for anything else, and both Blichfeld and Chekhovich having about as much overall NHL potential as Gushchin, but with a lower ceiling.
Adding Hatakka into the mix gives you a guy with low top four upside, pretty good bottom four upside, and good NHL depth upside - probably not unlike Chmelevski, but with less total NHL upside (plus the risk that he goes home to Finland if he can't stick). Melnichuk is in a similar boat - low starter upside, decent backup upside, and he can always return to Russia.
I know this sounds like I'm hitting on the European players, but I figure a player who stays in the AHL has some value to an NHL team, while a player who doesn't has zero value. Maybe this isn't a good way of looking at it.