I never made my mind up about instant travel in UO, I generally only used it for quick important business, but its presence helped keep my vast empty wastes vast and empty of other players, so I could wonder around unbothered. It also served as a big painted target to draw most reds into a few avoidable areas.
But you could see how their very existence made most tasks too easy to complete, I could spend my time slowly wondering from town to town chopping and processing untouched trees and collecting reagents and cotton because nobody ever went to those places.
I'd say the problem is more an excess of quests which ask you to go from point A, get an object at point B and then return it to point A