Mark Kern of Red 5 Studios is all about the idea that most of an MMO is wasted space. Not travel space that doesn't need to be there; no, Kern is talking about the huge amount of low-level content that gets played and discarded at a dizzying pace as players move past it. According to Kern, anywhere between 80-90% of the content in a given MMO is both expensive to craft and more or less irrelevant to the game after six months.
Kern stresses that the primary problem is that the cost of developing an MMO is raising while the time spent on content doesn't change, resulting in a neverending rush to produce more high-level content at a rate that's simply not realistic. He advocates more dynamic content, more scaling, and more flexibility in progression to help make development costs feel less like money flung into a pit for low-level content. If you're interested in the industry as a whole, it's worth a read.
[Thanks to Dengar for the tip!]