I've never seen the "all around player" ever turn out better than the scoring players.. Or at least very rarely. Usually the "all around" thing is used to justify their lower production and they end up as bottom 6 players with maybe a peak on a 2nd line somewhere.
First of all, last year both played in the OHL.
Tomasino
62 GP
40 goals
100 p
Robertson
46 GP (brackets are for a 62 game pace)
55 goals (74 goals)
86 points (115 points)
That is just a sizeable gap in production, and a literal historically good goal scoring campaign.
Then so far this year, both are PPG with their AHL teams, but it's been a small sample size for both.
Thus far, Robertson has the higher upside and more importantly the more valuable asset which is goal scoring. Teams have all around high temp guys all over, and yes ones who can score are very valuable. But nothing is more valuable than a 30 or 40 goal scorer which Robertson has realistic upside of.
Not to mention, Tomasino has been the more physically developed player and therefore had an advantage especially in the OHL. Robertson is under 5 foot 10 and was drafted at 160 pounds. He has some untapped potential once he gets a chance to pack on some muscle like Marner did and then can actually play his game in the pro's.