Bol Bol is talented, his small weight, motor/drive and injury issues is reason why he wasnt a top 10 pick, let alone 44th. If he works hard and stays healthy he will be a major steal.
Tacko Fall is just freakishly tall, doesnt even have basic basketball skills besides standing under rim blocking or putting in loose balls.
And he is not suppose to be much more either, in college basketball wasnt his main focus but was there for education in engineering. Getting attention and focus for NCAA was a surprise for him, swathing away the ball against Zion and rest of Duke elite players, headline grabbing games. But I very much doubt he will have real time in NBA, other then 10 day contracts like the one he has now with Celtics.
If giants like Boban Marjanovic who are legit decent Bigs have little to no chance to get minutes in the league, because he is simply too slow to keep up with everyone else, cant see any hope for Tacko Fall. Besides being tallest player in basketball since Manute Bol.