Well, when it comes to fanfic as long as the FC doesn't steal the position of the canon main chara and that they are well done, I'm cool with it. The style doesn't have to be the same not does it have to be linked to the main story. Basically, as long as it isn't something like My Immortal, I'm cool with it.
Ore that one if the writer wants to. Each writer has their own writing style and writes better in a certain way. So if they want to write in a slower pace, good. If they want to write in the action packed style that JP does, then good