Actually, that was a good idea. Forcing you to run the whole linear stretch back with no enemies/puzzles/anything would be completely pointless.
No. The good idea would've been to re-introduce mark and recall. Same effect, without making dungeons feel like some contrived circular made-for-adventurer-convenience structures.
Being able to cast Recall and quaffing as many potions as you like in combat, were among the many things that made MW too easy.
But having a Recall spell that worked only outside combat in Oblivion would have been nice.