While I would love to see three our four Dragonborn/Dawnguard sized DLC, the very fact that they are selling season passes suggests we shouldn't expect anything more than we got for Skyrim for that thirty dollar price tag. But then, maybe we will. This is their first time doing the season pass thing so maybe they should over-do it the first time around to create confidence in the next games season pass. They leave everybody feeling burned and they won't sell any passes for the next game.
As to large vs small, I want DLC like the two previously mentioned ones. Smaller DLC might be entertaining, but they also tend to be one off and done affairs. Both Dragonborn and Dawnguard expanded the game world beyond their actual quest content. I had reason to visit Solstheim both before and after the Dragonborn quest ... it became a new part of the game world. Revisiting the Soul Cairn (soul gems!), not to mention Fort Dawnguard and the Aetherium side quest also gave Dawnguard utility beyond it's main questline.
While I enjoyed DLC like The Pitt and Point Lookout, I never had any reason to return once it was over. Zeta and Anchorage added nothing substantial to the game world. Broken Steel at least tried.