I can't get enough of those who relish the 'no consequence' syndrome. Inaction and action should have a cause and effect, this pulls players in to their envirionment. If someone were to invade your house, sure you could ignore them but the consequence would be your property would be violated.
I'm a huge fan of meaningful consequences for choices and actions taken by the PC. From what little information we have so far about Skyrim's quests, I'm loving the details that suggest branching path quests for the Civil War (the Stormcloak/Prisoner encounter), where you can choose to either fight the Stormcloaks, free the prisoner or hand him a sword, possibly hurting your reputation with the Stormcloaks, or you can heed the Stormcloak's warning and let them pass, possibly hurting your reputation with the Empire, if that prisoner turns out to be an important Empire NPC.
However, putting time limits on quests doesn't really make sense for a TES game. Some people might play the game and finish the main quest in 30 hours but for many of us, single playthroughs of 300 -500 hours are pretty common for Oblivion and Morrowind. In fact some super long marathon playthroughs lasting over 1000 hours are not unheard of.
Many of us derive the most enjoyment out of each playthrough by stretching it out so it lasts as long as possible. Anything that makes sidequests or the main quest shorter detracts from the total playing time.