Pffft, full-length fic = anything >1K. Or whatever any given fest's required minimum is. :P
I don't think multi-pairing fests are intended to exclude anyone, but to cater to people who are open to a variety of pairings. Just as pairing-specific ones -- which were created later, likely as a response to the multi-pairing fests -- cater to those with strong pairing preferences.
I mean if you REALLY want Snape/Lucius, which fest do you participate in?
Well, assuming no Snape/Lucius fest exists, then you do one of three things:
1. Join a multi-pairing fest and hope that someone else joins who likes Snape/Lucius and feels like writing/drawing it, but realize they they might not and be equally happy with a different gift 2. Take part in a prompt-based fest instead, and hope someone takes your Snape/Lucius prompt 3. Start a Snape/Lucius fest
Seriously. I've seen a bunch of people (not directing this at you specifically; I've just seen a lot of stuff all over the place in the last two or three days) complaining about various aspects of fests and their formats recently. Really? If the existing fests don't cater to your interests and preferences, go start one that does.
Fest participation has changed so much over the last several years. Originally is was all, "Oh, wow, I'd love to get this or this or this or this... Squee, I got a gift!" And now people have very high expectations and are far more demanding. That's not necessarily an entirely bad thing; it means that HP fandom is full of amazing authors and artists and planners and organizers, and we all know it. But it also makes things increasingly difficult for the poor mods whose work is largely taken for granted these days. And it also makes people feel uncomfortable about participating in something that's supposed to be fun if they don't think that can meet the (excessively high?) expectations. ::looks pointedly at your comment::
Wow, it's not even September yet, and already the fest criticizing is epic this year. Is it any wonder so many of the mods have chosen not to rerun their fests in the last couple of seasons??
Anyway. Comment (and my brain) sort of went all over the place there. The main point (I think!) was that different fests cater to different interests and preferences, and if one doesn't exist that meets yours, well, sucks to be you. :P And that maybe people in general need to get back to being a little bit more reasonable and flexible in their expectations.
(Can you tell that I've been waiting to write up a totally tl;dr post about all of this? LOL)