I, of course, immediately looked at it and thought: this calls for science. Because clearly what we need are definitive numbers for each of these values for many, many fandoms, so that they can be plotted on graphs. This will make me HAPPY. Possibly it will also make you happy - or perhaps you are just interested in increasing overall happiness in the universe! - in which case I direct you behind the cut.
ETA: lolitakun has provided us with some preliminary scientific results here. Go and behold!
A quick note on the selection of the fandoms: I picked ones I thought a lot of people would have opinions on. If I left something critical out, feel free to tell me in the comments.
A quick note on voting: When I say "slashy," I include femslash. Buffy/Faith, Gabrielle/Xena - these are pairings worth considering! Also, if you haven't seen an episode of the show, please don't vote on canon writing quality. (Ideally, you would have seen three! Or even more!) But if you think you can make a fair estimate of slashiness based on vids or YouTube pieces or transcripts, by all means, vote on that.
ETA: For quality, 1 = worse than anything you could find on fanfiction.net, even if you were funded by a grant solely for the purpose of finding the worst writing the world has ever known. 10 = genius unparalleled. For slashiness, 1 = straighter than a ruler. 10 = they could suck cocks or finger each other right there on the screen and it would only reduce the overall slashiness. Thanks for pointing out the ambiguity, lolaraincoat!
And now it's time for...SCIENCE.
D. C. Universe (comics only, for this): how slashy?
D. C. Universe (comics only): canon writing quality?
Doctor Who/Torchwood (what we're now calling the Seussiverse in this household): how slashy?
Doctor Who/Torchwood: canon writing quality?
due South: how slashy?
due South: canon writing quality?
Harry Potter: how slashy?
Harry Potter: canon writing quality?
Hercules/Xena: how slashy?
Hercules/Xena: canon writing quality?
Highlander: how slashy?
Highlander: canon writing quality?
House: how slashy?
House: canon writing quality?
Jossverse: how slashy?
Jossverse: canon writing quality?
Lord of the Rings (trilogy, not RPS): how slashy?
Lord of the Rings: canon writing quality?
Merlin: how slashy?
Merlin: canon writing quality?
Stargate: SG-1: how slashy?
Stargate: SG-1: canon writing quality?
Stargate: SGA: how slashy?
Stargate: SGA: canon writing quality?
Smallville: how slashy?
Smallville: canon writing quality?
Star Trek: TOS: how slashy?
Star Trek: TOS: canon writing quality?
Supernatural: how slashy?
Supernatural: canon writing quality?
The Sentinel: how slashy?
The Sentinel: canon writing quality?