By that logic, we can all say that Inuyasha and Young Link (Who were cut to begin with) are shoo-ins because of veteran status. Granted the latter is now relevant thanks to to Majora's Mask 3D and could be a last minute clone, the former is illogical since there will be no more anime reps and Inuyasha lacks "muh popularity" in comparison to the Big 3. While Mr. Incredible may return just because of the upcoming sequel and "teasing", Our Ogrelord is still more likely since he garnered a massive cult fandom everywhere (From Miiverse to Tumblr) and he's still churning out holiday specials despite the last film being released years ago. Did I forget to mention that Shrek has the moveset potential to be more unique that someone that could do nothing but punch and smash things (Ogre strength, drop kicks, farting, "the roar", armored headbutts, pro-wrestling, ect.)?
Inb4 "Shrek would be a Wario clone".