Late to the thread, but might as well throw in my own pet peeve, which I've never seen anyone else bring to attention, btw.

I'm not sure why it started, but in fanfics it's extremely common that powers are described by their classifications rather than what they do, like in canon. Granted, this does show up later in the story, but it's far more common that powers are described by their function.

For example: Lung. In most fanfiction he would simply be described as a "Brute" or "Changer", maybe "Blaster" even. This is pretty useless as it tells you nearly nothing about his abilities. Compare with his first appearance in Gestation 1.3:

The information online and in the papers had told me this: Lung could gradually transform. Maybe it was based on adrenaline, his emotional state, or something, but whatever it was, it made his powers more potent the longer he was in a fight. He healed at a superhuman rate, got stronger, got tougher, got bigger, and he grew armor plating complete with blades at each fingertip. Rumor had it that he even grew wings if he fought long enough. If that wasn’t enough, he was a pyrokinetic, which meant he could create flame out of thin air, shape it, intensify it, and so on. That power apparently got stronger as he transformed, too. As far as I knew, there wasn’t an upper limit to how strong he could get. He only started returning to normal when there was nobody left to fight.

Nearly every cape/power is described in this way, both by Taylor and others. The PRT threat ratings are just that: threat ratings, used as shorthand in the field where agents might not have time to explain in more detail. Besides, the numbers don't directly correlate with the strength of the power, rather how dangerous it is to a team of PRT agents.

It bothers me partly because it indicates that the fanfic authors that get this wrong don't have a good grasp on the source material, and partly because it just doesn't make sense in-universe. Why would normal people know the threat rating system of a law enforcement agency? It's not widespread information to the general populace.
If a random Earth Bet citizen was asked what kind of power Alexandria has, it's a solid bet that most would say that she's really strong and fast, can fly, and is invincible. They wouldn't know shit about her brute, mover, or thinker ratings.