These characters fall under the domain of a 'Mary Sue' (female) or 'Gary Sue' (male) ... "Mary Sue" today has changed from its original meaning and now carries a generalized, although not universal, connotation of wish-fulfillment and is commonly associated with self-insertion. True self-insertion is a literal and generally undisguised representation of the author; most characters described as "Mary Sues" are not, though they are often called "proxies" for the author. The negative connotation comes from this "wish-fulfillment" implication: the "Mary Sue" is judged as a poorly developed character, too perfect and lacking in realism or authenticism to be interesting; only able to exist in an idealized fiction controlled entirely by the author.

These forms, and abilities are there not because they fit your setting or genre ( like say; 'I have been cursed, because I was bitten by a were-wolf, and now, on every full moon go on a crazy killing spree that fills me with  guilt and angst) but rather, because you gave your character abilities and powers to cover all possible situations in order to avoid, or overcome conflict (rawr I'm a powerful dragon when I wanna be!) getting in the way of your character being 'Cool'.

But the thing most of these people, whom have had such characters for 10+ years? They've failed to realize: The conflict they're effortlessly overcoming, avoiding, or pushing off with the aces they always have up their sleeves? That conflict ... and the TROUBLE that NORMAL CHARACTERS go through to try to overcome it (i.e. John Snow, Luke Skywalker, Arya Stark, Corwin of Amber, The Father from 'Taken', etc..) is what the entire story is about.

It's actually the fact that your character HAS so many aces, powers, and forms ... that makes your character Uncool. This is the fundamental difference between Iron Man 1 and Ironman 3. Why the fuck.. didn't he just.. open up with the 'House Party' Protocol? ... Resorting to "I'm Not Left Handed" only works when you are intentionally mocking a trope as even 'The Princess Bride' was doing; i.e. Intentionally not taking it's own genre seriously. The Princess Bride was satire about stories and movies.

If you're a serious role-player? If your "ten (or more) years of experience playing this character" meant something? You'd understand that other people's investment in the story and their character's should mean enough that you take their participation and characters seriously by taking your own seriously.

You don't strike gold, and write an award winning character the first time you do it. Continuous, improvised writing just doesn't work like that. You shouldn't be bragging about only having had one character 'all these years'.