PHP 5.3 is declared End of Life as of 15 Aug 2014: http://php.net/eol.php. PHP 5.2 is declared End of Life for almost 4 years now, so I think it's time to say goodbye for a obsolete version of PHP.
Dropping this very old version of PHP makes it easier to make themes and plugins for WordPress, because you can use newer functions and remove legacy code (which make the code easier to maintain and improve). PHP 5.3 introduces many useful features for themes, plugins and the WordPress core.
Dear developers, please drop this version and share your thoughts about supporting libraries in general (php, mysql, etc.). I'm using Ubuntu and developing with Symfony2 as well and I love their transparency about support (i.e. LTS version).