Well, I suppose if I were a betting person, this is what I would guess for future IAH service:

-- Durango. Currently served direct from Chicago on Mexicana. Lots of families traveling back and forth.

-- Huatulco. A somewhat undiscovered beach resort in the state of Oaxaca.

-- La Paz, Baja California? Not too much traffic, but currently extremely limited access from La Pax to the eastern US. I'm surprised HP hasn't picked up La Paz yet- I'd put it ahead of Guaymas.

-- Maybe Oaxaca, Oaxaca: lots of European tourists. If CO can fly a bunch of people on their metal from Europe to connect onto Oaxaca, the service may be good for, say, seasonal or 3 times weekly flights.

-- Queretaro? Close to the foreigner enclave of San Miguel de Allende- but then again, it's not too far from Leon.

Service to Puebla came and went. Service to Zacatecas came and went- although Mexicana still runs direct service from Zacatecas to Chicago, LA, and Oakland.

I suppose once CO exhausts about all other Mexico markets they may open service to Tuxtla Gutierrez, Chiapas, but I think loads would be iffy until things settle politically. I can see the Cd. del Carmen flight continuing to Tuxtla.