I completely missed this when it was originally published, probably due to the holidays, and I wager plenty of others did as well. Raph Koster (of Ultima Online and Star Wars Galaxies fame) has an exceptional essay titled "Do levels suck?" on his site going into detail on why, wait for it..., levels suck. This was posted to the MUD-DEV mailing list, and is aimed primarily towards designers, but any serious gamer will be able to see the merits in the argument as well just by comparing their gaming experiences.
From a gamer's perspective, I agree. In fact, the online game designs I've appreciated the most have been the ones with the lowest barrier to entry for a new player to contribute to an established group. This is the reason I enjoyed Ultima Online so much - I never felt that any part of the world or any other players were 'out of my league.' Despite the fact that the world and content were much smaller than its contemporaries, the game still felt large because I was never confined to a small range of suitable content.
This is also one of the things that is very cool in EVE, which I was sucked into trying after reading past articles from our authors. Even as a new player, I could easily team up with players that had been around for a year or more, and feel like I was contributing.
I think this is also a good example of why I have a hard time picking up an MMO significantly later than launch. There's just not that many people in the middle areas, so most of the content gets added at the top, which you'll need to hurtle yourself through all the abandoned middle content to get to. I'm anxiously awaiting the next game that sheds the partitioning and provides a wealth of content accessible to the entire playerbase.