So far i am only in Whiterun and i am wondering how big is the game are guild quest-lines considerably longer than those in oblivion ? How does it compare to Morrowind ? (disregard computer generated quests)

Well the map is little smaller than previous Oblivion, but was hoping the modders will make extra landmasses near Skyrim to complete the rest of continents. Only High Rock, Hammerfell, Cyrodill and Morrowind are connected to Skyrim. It will be awhile before they are complete, if the toolset is not too complex to use.