Johansen is, in my opinion, in a very similar position as Voracek was before he got traded.
Johansen has the physical ability. He has the defensive ability. What he lacks is the offensive breakthrough and mental maturity. If you compare the two, they are very similar in style and what they choose to do with the puck. Jake was a bit faster and Joey is a little more lanky (plus playing center he has greater defensive responsibility).
If Johansen gets more confidence, finds some chemistry, and earns the trust of the coaches, he really can be a PPG player. That said, those are 3 difficult elements to master and we've never really had a forward break out like that before.