I don't think that any GOOD and COMPLIANT fanfiction can be written until the end of the trilogy.

(Just my little opinion)

As a writer I feel that any fanfiction would need to be pretty great

Agreed. It's just that anything that anyone writes now will be weird when CoG comes out.

so true

Yeah... so we'll have to wait, sadly...

it's ok, we'll live

once, it made me sad... I never went back

I don't know, we'll see what comes of it I guess, there's a whole year to see what people can do

Kaylee, I am forever replacing the real ending with that in my mind. Thanks for posting that.
All the MI fics I've read so far have been very.....well, most of them lack something.
There are ones like this one that make me giggle and wish it really happened.

I don't like reading fanfictions about AUs and stuff. I mostly like oneshots that could be placed at any time/missing scene fics. So I just ignore the CoG fanfics and read the oneshots. Good fanfictions can be written before CoG, but there will be better ones once it's out, methinks.

I've read a few oneshots I liked on FF.net. -too lazy to get links-

EDIT:
For example, I simply adored this insightful Alec drabble. (I now have this set in my mind - that that is the reason that Alec doesn't fight - like it really happened in the series.) Unless the reason Alec doesn't fight becomes a pivotal plot point, there really is no harm in this kind of fanfic being written before the last installment comes out.

As a fanfiction-writer I, of course, enjoy fanfictions, whether or not a trilogy has ended (:
Of course it's always more fun to read, when you know all of the books, but on the other hand, are there a lot of good ones out there too :]

So, my opinion is that it's great to read and give you another perspective you maybe hadn't before; or fulfilled some of your dreams or hopes for CoG (:

But again, I understand why people don't like to read 'em, before a series has ended