i think fast travel ruins roleplay, personally. How can you have roadside bandits when everyone just catches an insta-ride on a carriage? Eliminates a style of RP, it does.
I like the size, not only does it give the chance for more rp, but while i am walking down i often question my characters motives, why does he do this and that, i then change it accordingly if i think i am straying from what my character would do.