Mary Sue- A character claiming to be related to a popular character (I.e: Saying you're related to a king, queen, etc. Also being in relationship with a popular character. Take example of a Sonic the Hedgehog OC and pairing it up with Sonic or Shadow.) or having no flaws, being 'perfect'.
It's a term commonly used if a character has no flaws or is really popular for no reason, idk. People just love to slap the term everyfuckingwhere whenever they nitpick at what they don't like about a character.
I see where you are coming from and totally respect your opinion. However, as a writer I know that Mary Sues can be good and bad in some situations. Example would be a magical person to have strong abilities in a non-magical realm. Another would be an immortal being that can destroy you in three second flat.
Those are really the traits of a character that bother me the most.
MLP is so good because the mane six have good traits and bad traits and personalities. They thought through. Sometimes I feel people do not put much effort into their OC. Piling up good traits without any bad ones can be MS, as well as the opposite.
Anyway, argument aside, I do love the coloring on this stamp.
I think it depends on how unrealistically awesome the character winds up being lol.
If the character is like the author, but is not 100% infallible then it is fine. However, the original Mary Sue from the original Star Trek fanfic who was so unrealistic that now we have the term Mary Sue link: www.jessesword.com/sf/view/109… <--um here. In the fanfic Mary Sue was the youngest officer in Starfleet history, awesome at everything from karate to zoology, everyone liked her, and was missed by everyone when she perished.