Who deserves to be in the most? I´d say Snake/Big Boss, since Snake/Big Boss were on PS1, PS2, PS3 and PSP and most of the games were Sony exclusive at some point.
Crash, Spyro and Abe also deserve to be in, imo. All of these characters were icons, especially on PS1.
To represent Playstation today:
To represent Playstation's Legacy:
Spyro the Dragon
Also with the news that Gravity Rush will be included in the Vita PS Plus package it seems Sony are proud of the game, believe in it, and therefore Kat is the standout choice for a Vita rep, she deserves a spot for that sake.
1st party candidates would be Rudy Roughknight, Dart Feld, Robbit, and maybe a Battle Arena Toshinden character though Sony isn't publishing that license anymore, kind of like Crash.
Crash is the very least deserving to be in this game in my IMO. Not saying he shouldn't be in the game but he isn't as important as Dart Feld and Uber hero that's for sure