Ah... so many things I could talk about, here... :,D
In general, I feel like I can look back on just about every RP character of mine -- including the ones that I'm technically still playing, but that I started playing quite a ways back, like in my long-lived RP's -- and feel like I played them as too much of a nervous wreck... This is something that I still struggle with, for whatever reason. >.>" But it's much more noticeable in my older posts.
As for specific examples... gah. Moon was way too dark and brooding in his early incarnations, but, hey, what else would you expect from one of my first ever characters? In somewhat-later incarnations, I remember him being a bit more of a dork-wolf than the much more dark and intriguing creature he was originally designed as, but I still feel like, even by that point, it was still hard to strike a good balance and not make him excessively broody or emotional. Also, I gave him a pet bird for some reason? He rescued her as a baby bird that fell out of her nest, which was supposed to show his heroic and caring side. And, as an adult, that bird always followed him around and acted sort of as a "sidekick" -- which made sense in the earliest incarnations of Moon's story, which was very much a "talking animals" sort of tale (I mean, Moon himself is a wolf), and so Goldie (the bird) was considerably anthropomorphized. But as the lore for all of that evolved and changed and got recycled a number of times, that quality started to disappear -- Moon still had human-level intelligence (because he's a ~magic~ wolf), and he could still understand Goldie, because being able to talk to animal species was one of his powers. But by that point, I never gave Goldie any real "dialogue", and she acted a lot more like a regular bird, with everything she "said" being interpreted through Moon. But then that meant that she was just... there, and rarely had any importance in anything, except for if she went missing and Moon was worried about her or something. Looking back on it, it was just really pointless to include her at all. If I ever re-use Moon again, Goldie probably won't be included.
Muse (yes, I have a character named "Muse") always did way too much to save the players' asses instead of letting them overcome obstacles on their own (particularly in the early stages of WttG and WBttG), and I was always very inconsistent about what his powers were even capable of. I've gotten so annoyed by it at this point that I recently let him get captured by the Big Bad of the RP so that the players can finally prove their own strength for the final arc of the RP by rescuing him.
Every attempt I've ever made at creating an "evil organization" filled with faceless NPC henchmen has always just been so laughable in hindsight. They're supposed to be intimidating but nothing they do makes any sense. Why do I do this.
Also, I seem to have an issue with creating God-cats that create endless deus ex machinas...? I have done this in two RP's, and didn't notice the similarities until well after the 2nd God-cat was already an established character. They don't talk, they're implied to be more-or-less intelligent and also ~know things~ about the plot but they still act like normal cats most of the time (I mean, the first one could fly, which isn't exactly normal cat behavior, but, details), and so they never even felt like real characters. They were just... little furry bundles of plot-convenience that were just sort of there. One of them is still in one of my current RP's and I've certainly been trying to rely on him less and less to get things from point A to point B, but like... yeah, this seems like a really weirdly specific misstep to keep accidentally doing over and over.