Crosby = proven 100 pt player
MacKinnon = overhyped rookie who is really more of an 80-85 point player
McDavid = generational talent to the scouts, but 0 NHL games. has a chance of being a Crosby type but not worth the risk.
Crosby is still young enough where you can expect at least another 5 years at 100 pts, and probably 10 years of 70 points or more. Only in 5 years do I think MacKinnon or McDavid have even a chance of matching him, and if you're looking that far ahead I think you're putting too much emphasis on the future. Yes dynasty leagues are always about looking to get younger, but your priority at the beginning of a league should be getting guys entering/in their prime. Don't think it's wise to shoot yourself in the foot from day one. Nobody should begin a keeper league with a rebuilding agenda.