In reply to LPH.

"This leaves a big opening for an easily installed site, extremely optimized for fast loading, and hooked for plugin developers to expand the features of the site without slowing things down."

- isn't this idea (which incidentally sounds a lot like WordPress - and note: contrary to popular belief, WordPress isn't inherently slow these days) going to also be a hassle to maintain?

About the only system I can think of that's significantly easier to maintain than WP is a static html/css website, which gives you nowhere near the functionality -- especially in terms of content management/creation!