That doesn't mean much, given that Hulk, Maldonado and Grosjean were all in GP2 at the same time. Maldonado also broke his collarbone and missed the last four rounds of his rookie season, having previously posted good results including a win at Monaco.
It's difficult to quantify (but quite fun!
![Stick Out Tongue :p :p](/styles/default/xenforo/vbSmilies/Normal/tongue.gif)
) as obviously the rest of the field matters a lot (and team does make some difference) but as for all of the GP2 winners and which season they won it looks like...
2005- Nico Rosberg (ART Grand Prix) 1st Season.
2006- Lewis Hamilton (ART Grand Prix) 1st Season.
2007- Timo Glock (iSport International) 2nd Season.
2008- Giorgio Pantano (Racing Engineering) 4th Season.
2009- Nico Hülkenberg (ART Grand Prix) 1st Season.
2010- Pastor Maldonado (Rapax) 4th Season (3rd Full season).
2011- Romain Grosjean (DAMS) 4th Season (2nd Full season).
2012- Davide Valsecchi (DAMS) 5th (!) Season.
2013- Fabio Leimer (Racing Engineering) 4th Season.
Looking at that it's easy to see why some drivers are overlooked, if they are 2-3 seasons into a racing series and battling rookies in their 1st season it doesn't look all that spectacular when they (eventually) win it.