The EXTREMELY unrealistic colours and patterns. Why not make your OCs green or something if you're going to be THAT unrealistic? I don't care about genetics in fanfics because not everyone knows about genetics (But the Erins should!)
Too many tortie toms! It's a LOT rarer than you think. And too many blue-eyed cats. It's VERY, VERY rare for solid-colored cats to have blue eyes, like almost impossibly rare. However, you can make your bicolor cats realistically blue-eyed.
The crappy grammar and spelling. Not everyone is fluent at English, but some of the books I have seen are barely literate. Now to be fair, this applies to all fandoms.
The improper names! Here's some I've found:
Winterfrost
Autumnleaf
Summersky
Starpelt"Star" is a forbidden prefix. Warriors do not know what Autumn, Summer and Winter are! Spring is a valid prefix, though.
YOU ARE READING
Warrior Cats rant!
FanfictionMy criticism on the series. If you get offended easily then this book is not for you but you're still welcome to read it :)