I remember this topic coming up in a team meeting or two, and though I had nothing to do with the original concept of the time limit, I was always in favor of it. It made sense to me and instilled a harshness to the atmosphere that wouldn't have been there otherwise. That is what I think we as a team all agreed upon: this game needed to constantly demonstrate that it was set within an unforgiving environment.
Then again, I am also a huge fan of the Realms of Arkania series which would punish players mercilessly for forgetting things like blankets or eating utensils.
Perhaps it's a good thing I have gotten out of the industry. Nobody is a glutton for punishment anymore; I would have no idea how to appeal to today's gamer and still create something I'd want to play myself.
Besides, nobody lets artists into design meetings anymore.