Alucard -- CSS is designed to degrade well on older browsers that do not support it, or only support part of it.
It should degrade a lot better than using <table> and <font> which can cause problems in very old browsers. And <font> can cause some serious problems with some accessibility aids as they may not be able to override the designer's insistance on specific fonts and sizes. (DMOZ uses a lot of <table> and <font> tags).
But that's all theory, really. The real question is how much better (or worse) is it for actual real users using older technology. That needs real responses from those people, rather than theory. Plus of course some demos for them to play with...which is, more-or-less, where this thread started.
In practice some things may get better, and some worse. For example, CSS-based designs tend to be smaller (much smaller if the CSS is in an external file and cached) so that improves accessibility for people on slow lines, or those using cell phones for access. That could increase the range of people who may consider becoming editors.
"In theory, there is no difference between theory and practice. But, in practice, there is." --- Jan L.A. van de Snepscheut. (tip of the hat to kctipton).