There wont be any major Tamriel province as DLC.
And why not? look at bethesda, every new game they've made in the past few years, have seen their DLC getting bigger and bigger, and with steam and DLC in general as well as pressure from not just the tes community but the console comminities pushing for bigger and better DLc, i think other provinces have a good chance. Sure it'll be more expensive but it's a feasible option.
My bet is that the next full tes game will span over at least 2 provinces, the next generation of consoles are looking towards blu-ray disks which means way more storage space on disk so companies wont have to limit pc renditions to be of console size disks...
DLC today, tomorrow - blu ray. It makes more money to have DLC while limiting the cost of making disk-copies, so yeah, why
wouldn't they make other province DLC?
Akavir, no, a bundle of the southern provinces - yes. Morrowind could come back as DLC, and hmm, partial areas of cyrodil will probly be included in future games or DLC to help push story forward. but only areas relevent to the current game's setting/province(s)