I agree Mark, but the default 12px size and 120% line-height makes for poor readability in my opinion. Most Joomla templates out of the box will use a line-height of '1.5', or '1.6', vs '120%' (using % isn't always recommended). It's great that the user can change the size of the font as needed, but I'd rather keep options limited for the user in order to maintain a standard look and feel throughout the site. I don't know of too many Joomla templates that use a font-size of 12px as the default size for the body tag.
Maybe something to consider adding in a future release. I'm starting to really enjoy the new EB5 editor, but for me, having a default preset font-size would be one less step on the user's part when he/she is adding an entry.
Thanks.