I'm still reading the thread, so someone may have said this already, but OC/neo-trad as it is defined here is how I've been trying to play since I started roleplaying, back in 2001, so it's not something new. And it doesn't have to do with PC empowerment only; I love it and I'm mostly a forever GM!
From my perspective, OC/neo-trad follows on an ancient tradition of storytelling: that of plot coming from the protagonists' own internal struggles, and not (only) as some external plot in need of solving. When one adapts that style of storytelling to TTRPGs, the result is gaming systems like
Fate or gaming philosophies like PbtA or FitD.
Fate is trying to be OC/neo-trad (especially
Fate Core), but I'd say the best modern example, in my opinion, is PbtA games. The way I run (and whenever I get the chance to play) them, a PbtA offers you a character archetype, with a character arc already included in there. That's why we say that PbtA playbooks aren't classes/professions/etc.
Another thing I wanted to mention is that the best OC/neo-trad players I've played with have no desire to "win all the time" as someone said. On the contrary: they're often the ones proposing dramatically devastating conundrums for their characters. They don't mind losing—and losing
big, in a manner that changes their characters forever. What they care about is getting to experience a dramatic story that's centered on them, where their characters are the protagonists, and that their actions, for good or ill, will have great repercussions in the world around them. Sometimes the world around them is a little town (
Monsterhearts 2), a great city (
Masks: A New Generation), or even their whole fictional world (
Avatar Legends,
Root: The RPG, and even my own PbtA,
Against the Odds).
Sorry for tooting my own horn here but, as its designer, I feel that
Against the Odds is a good example of what "heroic fantasy OC/neo-trad" can look like. The PCs are heroes, but their conflicts go way beyond killing monsters, gathering loot, or having enough torches/rations. It's about each character's inner sense of self, of doing things that'll forever haunt you to "save the world", and how often great heroes are only so because they died before they turned into villains.