I'm looking through my reviews, and there is an older anonymous review which says the following.

"But what about OC-centric for NextGen? Is there really a rule of fanfiction that says you can't add in new characters/use characters when they aren't needed? The writers should have a freedom, shouldn't they? (But it's another issue entirely when their stories turn out horrible.)"

I never really addressed the points in the comment I think, but what does it mean to have freedom as a writer? Does it really mean a writer is allowed to do anything they want to? What does it mean that one is allowed to do something?

At a simple glance, the answer to the readers question may seem that, yes, a writer should have the freedom to do what they want. Their words should not be censored by another person, and they should have the freedom to do as they please. However, I think the integral issue here is, should one always do what they want to do? It's not about someone preventing yourself from doing something, but instead about the writer choosing not to do something – what they want to do – in favor of something else – what they know works better.

The funny thing is, that rule about characters being needed? It's actually not a fanfiction rule, but a creative writing rule. Says Mark Twain, "the personages in a tale, both dead and alive, shall exhibit a sufficient excuse for being there." That's what it means to be needed. They've got a reason to exist within the story, which brings up the question. If that OC isn't needed, why are you even using them? You can't argue that it "makes the story good", because it really doesn't. Unneeded characters bog the story down, but is unneeded detail.

Which brings me to another one of Mark Twain's rules. "The episodes of a tale shall be necessary parts of the tale, and shall help develop it." One of the major problems with many Next Generation fics comes down to the fact even when there are canon next generation characters, the material becomes bogged down with unnecessary parts. The writer sees these canon characters as blank slates because they've not been developed yet, so they can do what they want, but the writer doesn't know what they want to do. They have no direction.

When one adds OCs in and makes the next generation OC-centric, well, things will 99% of the time end up just being worse in that department. However, the other issue is the stories tend to become so detached from the canon material, that they're not fanfic anymore, but original fic.

Also, please don't pull the freedom card. When one is a new to writing, it is actually better to work within the rules and figure out your style and what works and doesn't before attempting to break the rules. Mind you, this also is with the understanding that you know what those rules are.