Well for me this applies to the RPF side of the fandom. I'e never really made it to Wincest regularly. I'm a fan of switching and bottom Jared but almost always write bottom Jensen. Damned muse.

I don't warn for top/bottom and I don't plan to start. I use an expansive list of tags and still there will invariably be someone that is upset because I didn't tag for this or didn't tag for that. Honestly, how many tags can you use before it requires a word count of it's own?

I agree with meus_venator about the name before the slash should represent the top or aggressor. It's a simple solution and requires no extra tags!