the comparisons aren't working so well for me. Jackson will be a scorer in the NBA, and elite on defense/rebounding/passing. He brings way more to the table than Roberson. His less than ideal shooting may keep him from superstardom....have to wait and see. But he can definitely score in other ways...dunks, floaters, drives, etc..
Tatum will be an even better scorer than Jackson, but most likely be a less dynamic player...not as active, with defense and passing not as good Jackson.
As far as who will have a better career between Jackson and Tatum I have no clue. If I were a team like Phoenix who has a bunch of shooters already, I'd definitely draft Jackson. The Celtics have Smart, Brown and Crowder. So I think the slightly bigger and better scoring Tatum fits the Celtics better. Actually I can only see Danny choosing Jackson over Tatum if Smart is traded. Even though they play different positions, a Brad Stevens style team can only have so many not-great shooters who are awesome in other ways.
However, if Bradley goes out in a trade I could maybe see a starting 5 of:
Smart, IT, Jackson, Shooter, Horford.......with Brown and hopefully more shooting off the bench than the Celtics currently possess. Compare that to the possible eventual: Smart, IT, Brown, Tatum, Horford. Hard one to call for me between those two....who would be the PF shooter in the first lineup?
Can Tatum handle a bunch of minutes at PF? And then there are a bunch of keep-Bradley lineups to consider. IF Bradley is kept and Smart traded (unlikely scenario?), then I'd take Jackson over Tatum.
Jackson is my favorite college player. He has a relentless quality to his game that Rondo and Smart both have. Without some trades though, the Celtics need Tatum.
I will just say that passing on Jackson is has some element of gamble. If he tweaks his jumper and becomes a good 3 point shooter, then he will a big time star with an enormous impact.
Top 4 for now for Celtics:
Fultz
Tatum
Jackson
Ball