One thing I said at the panel was that if Smallville had started with Clark and Lex's relationship where it was in season 5, there still would have been TONS of slash--it just would have been enemy slash rather than buddy slash. But their relationship is still extremely slashy, canonically speaking. It's just that in the first three seasons the fandom was dominated by buddy slashers, and they could only live in denial-land for so long. I'm just said there aren't more enemy slashers who have stepped in to fill the gaps; I know there is a fair amount of seasons 5-7 Clex, but not nearly as much as there is the potential to be.