I’m pretty sure the only one mad about red-reggy being called out in front of 6000 people for stealing something and submitting it would be reggy.
Also, any OC worth noticing has been developed.
aero-replies has established a pretty solid oc with a decent personality
dittoprize despite it a parody of surprise, has been established as a drunk asshole who can somehow make talking appliances.
Hell, even alternate versions of canon characters have taken time to develop the character.
ask-factory-scootaloo is still trying to get used to the factory
askdiscordwhooves has had some major developement
and even ask-king-sombra has developed a personality.
Any Character, OC or not, that is worth taking an interest has had, and will have, character development because developing a character doesn’t stop until after the story ends.
And FYI, the O in OC stands for Original. OC stands for Original Character.