Less white space -> more information on the page!
* Since version 2.0 there are settings!
(if the extension fails to start, try disabling and re-enabling it on the chrome://extensions page)
* Remove useless paddings for the most of the page elements
* Make buttons look as active clickable elements
* Add border around email compose text area
* Highlight the email row in the list on hover/focus
* Narrow down labels tree when always expanded; Widen it when hover-expanded
* Less space for top/search bar
* Disable animations
* Multi inbox section labels clearer design