The recent update to 2.0 has me thinking about the movie "The Aviator", about the life of Howard Hughes. One of the main themes is that he didn't look at simply achieving the next step, such as building an airplane to go a little higher than the previous, but to make the leap to the next logical level, such as flying completely above the weather in a comfortable, pressurized cabin. I'm offering the opinion that "TinyMCE" is small step in the right direction, but it's not the leap to the next level needed to take blogging functionality where it ultimately needs to go.
For a moment, try to divorce the benefits and functionality of "themes"--the overall look and feel of a blog--from posting--the publishing of content within individual posts. WP provides a very good basis for customizing the overall design. But other than the occasional "complete makeover", a blog design is a one-time, major activity that is only occasionally revisited. The main, continual activity is posting content.
I'm just throwing out the suggestion--the "challenge", if you will--that the "next big leap" forward should be editing/creating content on the same level as a word processor. Yes, it will fit the formatting parameters of the overall site design, but just as a word processor allows you to do everything from scribble a note to write a novel and include just about any form of media wherever desired, so should posting content.
We need the ability to be able to create ANY kind of content we wish, as we see fit, even if we only occasionally need it: Tables (even spreadsheets), images, audio, fonts, every iteration of formatting, etc., etc. so that while every post has the "look and feel" of the overall theme, the content can be created via a word processor-type interface that allows a post to be formatted with the ease and variety of choice that a word processor now provides.
This is not a veiled complaint, just offering an opinion about the one thing I think would take blogging to the next level. If there were drop-down menus for inserting graphics, charts, tables, audio, etc., etc. along with the ability to format them like a word processor, blogging would make the next leap in the area that will ultimately matter the most: Quality of content. I also think it would be a better bridge to those that don't care to ever create or tweak a theme but just want to create content. The word processor model is the most common "interface" out there.
Just my two pennies' worth.