The Themes Manager interface really needs to recognise folders or some other kind of ordering.
This is more of a problem for multi-user/MU/blog farms where one wants to offer numerous themes but it also a bugbear for developers.
Currently, if one orders one's themes in folders, those folders are ignored and the themes just lists in the one single long list which can expand over many pages.
At the very least, it would help if it recognised separate folders of themes and listed them separately. Other kinds of searchability would also help.
I also flagged up in bugtrack recently that once one chooses a theme, the Theme Manager then reverts back to page one ... which is also a PITA if you have many page of themes. it would be better to revert back to which ever page was chosen before.
Ditto, a drop down would probably be of more use that page number which only show 3 or 4 page numbers .... how do you get to page 8 or 11 when all you see is 1, 2, 3 ... 20.
IMHO, as developers we really should not be using up user time wastefully and instead making the product more streamlined and efficient.