Virtanen has just as much upside as Ehlers & Nylander IMO even though they may be more offensively gifted in junior/europe does not mean that will translate to the NHL.
McCann has a lot of un-tapped offensive potential including one of the best wrist shots in the draft. He was constantly given defensive zone starts and PK time because thats what he excels at.
Nichushkin does look like the better player at the moment but you have to remember that the Canucks were still considered a very good team at the 2013 draft, Nichushkin had already gone on record saying he would go back to the KHL if he didn't make the roster of the NHL team that drafted him and that was soething that Gillis & co. had no intention of happening (their roster was pretty much set) So had they drafted Nichushkin they would then have to explain to the fan base why they traded a stud young goalie for a guy who may not even join the team.
For some reason people want to continue with the Horvat-Nichushkin comps. I don't know why, every knew Nichushkin has a more rare skill set/size-speed combo, but that doesn't mean you're a better player in the long term. I also don't understand how putting up ~30 points with 1st line icetime is all that impressive.
That said, it looks like Vancouver has a similar styled prospect to Nichuchkin in Virtanen. Same style of game, although Virtanen has a plus shot whereas I'd say Nichushkin's is just average, although he probably has a better playmaking arsenal at this time.
I'm pretty content with how that's shaken out so far, and if Virtanen can focus on improving his board play (mostly just hanging onto the puck longer) he'll be even better moving forward.
Nichushkin is the better "prospect", but he also doesn't bring the shot/run you over factor.