Melendez improved his striking around that time, maybe a bit later. He first showed that against Masvidal. So he was basically a wrestler with improving stand-up back then, a ideal fight for an in-shape Penn.
The Edgar, Florian & Aoki fights tell little of how that fight would've gone down, their styles are too far apart from Melendez's to Penn's and vice versa. Thomson is the closest to Penn of Gil's opponents, Sherk & Diego the closest to Gil.
Anyone who likes to throw down in the pocket and uses freestyle takedowns at LW should be too basic for a 2009 Penn. Too slick in the pocket, has always the punching power & chin edge, his TDD and ability to get up were too good.