Parekh has what I consider to be kryptonite for a skilled player transitioning to the NHL, inconsistent compete levels driven by attitude (and possibly character) deficiencies. The evidence supporting how this may hold him back is a checkered history in excelling against higher competition, namely WJHC camp and Flames training camp and some documented attitude stuff. Small sample size but it's a red flag for me. Players that dominate jr on skill alone get a proceed with caution stamp in my books. Without the right attitude it can manifest itself in the form of lacking perseverance and ability to overcome adversity. The Josh Ho Sang lesson on the extreme end. That said it is really easy to be wrong about this, recently I thought Evan Bouchard had red flags for similar reasons. I don't think I was completely wrong there but he's obviously a good NHLer. Drouin was another one for me and I'm not sure I was wrong there.
Ryan Ellis is a bad example for whoever brought it up. In jr Ellis was universally respected in the league. He had leadership qualities well beyond his years, was a hard worker and generally likeable player. Recall that he didn't even participate in his D+1 all star skills comp because he was too good, instead he filled in as a guest judge over his peers and he made it fun and did it without any ego. He had a completely different kind of character and approach to the game. This, in my opinion, played a huge role in his ability to adapt once the going got tough in the NHL.
Yakemchk is more projectable than Parekh to me because of his character. His is quiet, humble, and has a bit of a lunch pale element to his game. He is willing to get dirty, physical and stick up for his teammates, there is even some old school violence there which tells me something (ostaphuk has the same thing for what it's worth). His offensive elements have more potential to translate to the NHL as well since a lot of it is based on engaging physically, using his frame to create space, beating players in close, coming in from the point and going to the dirty areas. I'm also convinced that Yak is taking his D to heart this year and that explains his point totals. If that is true that speaks volumes about his attitude, professionalism and dedication. I'm not sure Parekh has that same character fibre. Don't know the guy and don't watch as much OHL but I'm suspicious.
On the purely talent side to me Zayne Parekh has a more Erik Karlsson or Quinn Hughes type game whereas Yak is more Brent Burns. And for that my point would be that the former is harder to translate compared to the latter. But yeah, probably bigger returns if it hits. Although I would say the returns on that type of talent tend to be shorter term whereas the bigger offensive guys typically stretch their impact longer into their careers.
Anyway, all told I think Yak has a brighter future and the concern for this years point totals kind of make me laugh, especially juxtaposed to Parekh's continued point totals. Points mean nothing for these guys future, we know they have the talent. It's how they develop a pro game off the puck that will tell the story.