If fast travel were disabled there would need to be more ulterior options. In Morrowind, there were carriages between cities and towns (but not all), mage's guild teleporters, teleporters in the Strongholds that you could use after you cleared them of monsters, the mark/recall spells (which allowed you designate a location and teleport to it later), and two spells that returned you to the nearest temple/sanctuary. You had a lot of fast travel options, but it still made it easy for some places to be difficult to reach or require a proper journey.
Granted, in a very few places they still just disabled teleporting in a dungeon. That would have been a lot less annoying if it was a more hard and fast game mechanic, say for example there was some kind of anti-teleport object or monster that you could find and destroy, and prevented teleporting in an area of effect. An auto-walk button or even a time accelerator like in flight sims might have been nice, although it might also impact your ability to explore.
One thing is for sure- the ability to run without your fatigue dropping in Oblivion was an improvement, walking slowly everywhere was not missed. I rather liked how walking/sprinting was handled in Skyrim too (although I do miss having stats/items that made you faster).