Okay. Here is my rambling rant for the day:
Now, I have nothing against romance in fanfic. I have nothing against unusual and non-canon pairings. What I do object to, though, is… Well, several things.
1. Pairings as the be-all-and-end-all:
There are archives out there where the only way to search for stories is by pairings. I've read fanfic for over nine years now, in various fandoms, and it sometimes seems as if 90 percent of fanfic is purely about pairings. (It varies from fandom to fandom, of course.) An awful lot of fanfic consists of a few pages in which A suddenly realises out of the blue that he/she loves B, and they either exchange flowery declarations of love, or rip each other's clothes off.
Okay. Fine. I don't object to people writing it, or reading it… but I don't like it myself. I prefer longer stories with plot and character development, in which a growing romance between A and B might feature as one plot element, or might not. It might be a story that contains a pairing between A and B, but it's not a story about that pairing.
Or it might not contain a pairing at all. Well over half of the stories I've written don't contain romance at all, and many of my favourites ones to read. But it often seems to me that such stories are the overlooked side of fanfic, relegated to a "gen" section of archives, that no-one ever reads.
When I was writing X-Files fanfic, I used to write a very intense friendship between Mulder and Scully, but no actual romance. That really cut down my readers. Eventually I gave in, and I took that relationship a tiny bit further. Nothing really changed about my stories or my characterisation, but because I included a tiny chaste kiss once or twice, the story could be labelled "MSR" (Mulder/Scully romance) and suddenly I got a whole batch of new readers.
Which takes me onto…
Sometimes, the listing of pairings at the start of a story pretty much tell you the entire plot. "Obi-Wan/Mace. Qui-Gon/Jar-Jar, then eventually Obi-Wan/Qui-Gon, and Jar-Jar/Yoda". I don't want spoilers like this! I don't want any spoilers. I'd rather approach a story with no pre-conceptions.
Yes, I know that some people do really object to slash, so it's only fair to give them a warning. But I don't like seeing the actual pairing. I think this allows people to become set in their ways. "I don't like A and C together, so I won't even read this story."
This has two effects. One is that the reader might be missing a good story - one that might have convinced them of that pairing for the duration of the story, and given them a lot of pleasure. In my opinion, a good writer can make any pairing convincing, for the duration of the story…
Oops. The second effect is actually my third point:
3. Non-canon pairings that aren't justified within the story
With a warning given, the author knows they're preaching to the converted, so they don't need to try to justify their pairing and make it convincing. They know that the only people who've stuck around to read it are those who are already convinced.
I can accept any pairing, even wildly non-canon ones, if the author convinces me of it. A good author could make me believe utterly that Spike and Giles were in love, say, if they started from a canon base, and showed me the slow progression of their feelings. I would only believe it for the duration of that story, though. I wouldn't start seeing that relationship in actual episodes of Buffy, and if a second author also did the same pairing, I'd want them to go back to the start and convince me all over again.
By putting a warning at the start - "Spike/Giles" - then an author can think that the only people reading it are convinced of that non-canon pairing anyway, and they don't need to do that work to justify it and show it proceeding naturally.
Fanfic is supposed to be fun. I just hate it when I see people flamed because "it's obvious that" A and C can never be together, because "it's obvious that" A and B are meant for each other. I think pairings can easily become a "them and us" thing. People passionately believe in A and B, so refuse to read anything about B and C… Which is fine, of course, as long as they don't flame someone else for writing about B and C.
"Are you a A-and-B-er, or a B-and-C-er?"
"I don't care! I just want to read a good story!"