Honestly I can't really say anything more then most have already mentioned.
The pro's for both fighters is there is star power in both of those title match ups. Chael and Jones bring in some of the highest PPV numbers in the UFC, and we all know Dana loves that. GSP has openly expressed interest in fighting Diaz. We've yet to see GSP have a legitimate grudge with another fighter like he has with Diaz. Mixed with the star power and PPV numbers he brings in, this can easily be the highest PPV numbers card GSP has had.
I'd say 2 impressive wins from Chael and he's in. Hell a devastating win over Forest could possibly bump him to next in line alone. You know he's calling out Jones if he wins, and you know Dana see's the $$$ that'll come from that fight.
With Diaz, probably the same thing. 2 Solid wins against top 5 guys (at the max) and he's in there. But similar to Chael, he could easily get in after 1 fight, or even right after the Condit fight. Be it GSP wanting Diaz after he beats Condit, or Condit getting that rematch if he beats GSP.