I'm probably the lone stranger, but I actually disagree. STID worked better (to me) if you DIDN'T know who Khan is and I am probably alone in this, but feel TWOK definitely works better if you saw Space Seed. Otherwise, the brief recap to Chekov and Tyrell is kind of throwaway and all you're left with is seeing this crazy guy hunting Kirk and you don't really know why.
A film shouldn't depend upon one throwaway line to work.
But I realize it's practically sacrilege to at all nitpick TWOK or Space Seed.