I think the issue could be an overestimation of scale on Bioware's part. We are so used to the idea that we can zip along and travel from one side of our country/region in the course of a few hours/days (depending on their size). We no longer recognize how long it actually takes to travel even relatively short distances on foot. It takes a while to get anywhere on foot, really, and it's why you generally stayed longer than a day with the people you were visiting, unless they lived relatively nearby (like within a several kilometer radius).
Personally, I think Thedas is likely around the size of Europe, which means it would probably took a little longer than 5 days to get to Denerim from Redcliff. More like a full week, if they really hustled. Which they would be, because the capital city of Fereldan is being besieged by the Darkspawn. Then again, this is just my opinion, and the games and side literature tell a different story.
A tiny Thedas certainly explains why everyone's so apt to conquer other regions; they're being forced to fight over tiny parcels of land. 
I think we're just used to things happening in a rapid succession, so we tend to want to speed of the time-frames for when events occur in fiction.