I think $3m is high for most 1st or 2nd over-all draft picks. The Nathan MacKinnon's are few and far between. Definitely the exception than the norm as most 18 year-old's don't produce or even play much. The table values as proposed below are a very minor change. Any reduction at the top of the list is more than balanced out with an appropriate bump to the league minimum.
1 and 2 - 3.0M 2.5m
3 thru 5 - 2.5M 2.0m
6 thru 10 - 2.0M 1.6m
11 thru 17 - 1.5M 1.4m
18 thru 25 - 1.0M 1.2m
26 thru 30 - 500k 700k
30 thru 60 and over - 200k 500k
Well 1st overall picks usually do produce with the exception of Yakupov, even then he still put up good numbers in his rookie year, in the past 4 years of this league most 1st overall picks have been good-producers at the NHL and fantasy level. Here is the list going back to Rick
2001 Atlanta Thrashers Ilya Kovalchuk Russia Forward Spartak Moscow RSL
2002 Columbus Blue Jackets Rick Nash Canada Forward London Knights OHL
2003 Pittsburgh Penguins Marc-Andre Fleury Canada Goaltender Cape Breton Screaming Eagles QMJHL
2004 Washington Capitals Alexander Ovechkin ^ Russia Forward Dynamo Moscow RSL
2005 Pittsburgh Penguins Sidney Crosby Canada Forward Rimouski Oceanic QMJHL
2006 St. Louis Blues Erik Johnson USA Defenceman United States NTDP NAHL
2007 Chicago Blackhawks Patrick Kane ^ USA Forward London Knights OHL
2008 Tampa Bay Lightning Steven Stamkos Canada Forward Sarnia Sting OHL
2009 New York Islanders John Tavares Canada Forward London Knights OHL
2010 Edmonton Oilers Taylor Hall Canada Forward Windsor Spitfires OHL
2011 Edmonton Oilers Ryan Nugent-Hopkins Canada Forward Red Deer Rebels WHL
2012 Edmonton Oilers Nail Yakupov Russia Forward Sarnia Sting OHL
2013 Colorado Avalanche Nathan MacKinnon Canada Forward Halifax Mooseheads QMJHL
Pretty much all of these players produced, even Stamkos would didn't have a "great" rookie seaso still put up 100+ fantasy points in his rookie year. Yes MacKinnon is having a great year but all these first overall picks have produced in their first year at a decent rate.
Maybe changing it so #2 doesn't make the same would be something because off the top of my head the only #2 to produce as well was Landeskog?
Also just took a quick look and appears a 100 point scorer is in the top 50 at that position which isn't too bad either.