@Mario Peshev - Getting rid of TinyMCE and adding support for Markdown doesn't mean that standard WYSIWYG support will disappear. There are lots of other WYSIWYG solutions beyond TinyMCE. As much as I love Markdown, I agree that it isn't going to necessarily be something that the "average" user will want to adopt over traditional styling.

For part 2, the great thing about Markdown is that it works perfectly alongside regular HTML. So you can mix and match. So if you need to set a font size or padding (although, technically this should be stuff that's covered by CSS and you should either style inline or it should be referenced in your stylesheet -- the only element regarding "size" should be h1 - h6, which you call in Markdown using #. So ## Test ## equals a heading that is surrounded in tags.), all you do is just insert that stuff side-by-side.

You can check out the official syntax (http://daringfireball.net/projects/markdown/syntax) for more details. Basically from what I can tell, WordPress.com is just installing PHP-Markdown as a plugin to automatically process all Markdown text into HTML.

99.99% of all of my professional writing is done in Markdown and one of the reasons I'm so addicted to it is indeed because it lets me write for the web in a syntax that also works perfectly with CSS, JavaScript, code blocks and inline HTML.