IMO...
CMD is more in the style of Lemieux. A very specialized piece and excellent one man army.
Crosby is more in the style of Gretzky. A piece that can fit with basically anyone, typically top 1/2 players on a team while also a good general vs being a team's one man army.
I feel like in the end, both would win multiple cups on these new theoretical drafting teams. But I feel like Crosby's team would have less major fluctuations in the standings while McDavid's team would have more major fluctuations from season to season. Coincidentally, I think this is what OP's post was playing on as well. Crosby has the accolades and consistency in team standings. CMD has had the higher highs for personal accomplishments but lower lows for team performance and questions marks from age 26-35 because it hasn't happened yet.
Both have completely different approaches in addressing the roster weaknesses. Not to say CMD wouldn't rally his team, but his focus would be to elevate his game to overcome the onslaught from opposition. Crosby would rally the team more than CMD and attempt to elevate his teammates to overcome the opposition onslaught via committee. I'm not saying CMD cannot elevate guys. He shoed he can elevate guys like Yakupov. He just doesn't seemingly prefer doing that over taking matters into his own hands. Crosby has shown the opposite preference during his career in elevating teammates before elevating himself, but I don't know if it was partially a defense mechanism for him to do that because he was playing through some injuries in an era where that was done more often.
I also think in an alternate universe, based on different teams and mandates of those drafting CMD and Crosby, it could be reverse that Crosby is considered the one man army and McDavid the general who lowered his personal accolades and traded some of his health to elevate his teammates.
As for who to choose, I think you can't go wrong with either. It's just stylistic preferences on how you want to see your team play. I think Crosby would work better for the stylistic preference the Flames have gone with over time (more lunch pail sandpaper styled teams). Plus, knowing what we know now, the "Iggy" call is iconic.