A star this big in the SmackDown title hunt?
Here's what should happen:
Monday night, Del Rio and Swagger have a confrontation. Del Rio goads Swagger into taking his WrestleMania title shot now instead of WrestleMania. Some way, some how, he convinces him, maybe he makes fun of his lisp or something else that makes Swagger want to kick his ass, says if he's really a "real American" he'll fight him now. Whatever, SOMETHING. Del Rio buries Swagger in like a minute and "breaks his arm" with the armbar, quote on quote. That's their way to write out Swagger. They have a battle royale for a new #1 contender and Mark Henry wins the shot at Del Rio like he should've done in the first place.
Then, the next night on SmackDown, Zeb can get even MORE pissed off by claiming that the immigrants screwed America out of its right to hold the World Heavyweight Championship, but he's going to continue fighting these criminals. He calls Swagger a loser who didn't believe in America like he does, and debuts a new wrestler who's going to help him on this crusade. Insert some other wrestler on the roster/developmental wrestler. They pick a fight with Rey Mysterio or Sin Cara and go from there.
This other wrestler with Zeb gets built and built until Mania where he goes over Rey Mysterio/Sin Cara. Del Rio beats Mark Henry at Mania but Henry snaps and attacks Del Rio post match. Ziggler cashes in. Ziggler and Del Rio have Del Rio's rematch the next night on Raw and Del Rio is about to win when Zeb and this other wrestler cost Del Rio the match (Ziggler can go on to feud with Sheamus, Orton, some other face), and the Del Rio/Zeb/whoever program is back on, only without the title. Do a 3 to 4 month feud with them trading wins and Del Rio ultimately emerges triumphant and Zeb gets fed up and goes home.