ScreamingBansheila,
I have the same problem.
In my case, I am sticking to my story until it is done.
I have at least 4 plot bunnies before this stubborn one came along,
and they only have 1 chapter.

I can't seem to finish them.
The one I am working on, I can see the finish,

but not the others.
Go figure.
It is up to you. I love reading Mac fanfic as much as I love to write it. It keeps Mac alive in my heart.
I am sure your writing is just fine. Either way and what ever you decide, I look forward to read your Mac fanfic.