It is likely that Lott will resign by the end of the weekly news cycle; the media and the left of the aisle will high-five believing they won a victory...but have they really? Isn't Congress segregated by caucus and interest? The media doesn't have a great track record for hiring and/or promoting African-Americans into upper management; the face of the media is mostly white male.
Discounting the self-serving media frenzy, isn't the Lott temptest a variant of the unease between black and white America that came to a head during the Simpson trial? When modern racial politics exposed the big lie that liberals and conservatives alike denied. That the rend in our society created by slavery and racism is not so easily mended and that our system is still oppressive or inaccessible to many.
At the end of the day, after Lott relinquishes the leadership and the media focuses elsewhere, what will have changed on a granular level?