Khan looked good last night but still needs work before he's ready for a title shot. Romanov would be a step in the right direction.
If Diaz is stripped of the WBO belt then I can see Khan fighting for this in a couple of fights, if he fights and beats Romanov next, say early April, then I can see him fighting Katsidis in June for the WBO belt, which he would have a decent chance of winning.
Khan - Katsidis would be a fight of the year contender. I could see them both having to haul themselves up off the deck.
Depends if Khan can stay disciplined. If he can, he'll beat on Katsidis, should be able to jab the face off him and counter punch. He might get tempted in to a slugging match though and that gives Katsidis a chance.