As somebody who bought Little Big Planet day 1 and to this day, hype that game to the moon, the grim reality is that Sony's mascot will always be Crash Bandicoot. Once Crash left, the void will never be filled...well maybe Nathan Drake, but beyond that not a single game will make you think "Sony" outside of Gran Tursimo, Uncharted, and God of War.
Now back to Sackboy. It didn't helped that Sony didn't have a single clue to market most of their games around the PS3 era. Hence why Little Big Planet was a successful dud. Bad enough Sackboy is not much to be desired. Lets keep it a buck, this fukking thing does not scream "awww"
It looks like a turd with a zipper, but damn the games were fun to play.
Also, you got to factor in the PS3/360 era was open to the "dudebros". I mean monster chugging frag out shooting frat boys with the big toe hanging out of the sandals. Folks were busy playing Gears and in PS3 case, Killzone. So yeah Sackboy was sadly a flop in the eye of a beholder.
Overall, Crash>>>>Sackboy.