I live in Prince George, and so I've seen Popugaev play a lot when I've gone to watch my local junior hockey team (Cougars).
Now, you could look at his mid-season trade away from Moose Jaw as odd, since contending teams sitting near the top of the standings don't usually trade away one of their top scorers. We in PG were happy to receive him, though, since we sat at the top of our division for most of the year (ultimately, we did finish the regular season at 1st in our division). Of note, his scoring rate in the 2nd-half of the season (after the trade) was lower than the 1st-half.
Was it a question of effort (ie, the "lazy Russian" trope)? Or was it just a case of him still trying to adjust to a new city, with a new system and a new coach and new teammates? It will be interesting to see how he plays for the Cougars this upcoming season, now that he'll get to work with our coaches and players right from the get-go.
Also, the kid's still only 18 (he doesn't even turn 19 until after the season starts). And I can tell you, despite his age, he is massive. He's already 6'6" and if he can sort through those issues that caused him to fall into the 4th round, I'd say you've got a solid chance of turning him into an NHL-er. And really, considering the vast majority of 4th-round picks never amount to anything anyway, why not take a gamble on Popugaev's upside at 98th overall?