maybe the css in the default-theme, or the edit/richtext-routines.
For example, I made a testpage with a simple table.
1) the vertical spacing between the headers H1 and H2 is a bit much (and/or it inserts unwanted <br>).
2) there is a lot of empty lines before the table.
As a workaround, to avoid the blank lines, just delete all the linebreaks.
But that makes the html-code very much unreadable and hard to maintain
so I don't consider that workaround an acceptable solution.
BTW, <br /> are also added to lists, resulting in an extra empty line
after each list-item.
Edit: this bug has already been reported back at v0.4.1
There was a proposed fix, but I'm not sure what has happened to it.