It will be good to allow point symbol in the network's site name, when in subdirectory mode.
This is useful, when doing site name from name's first letter and surname such as "examlple.com/n.surname"
I use such names about two years on my WordPress networks, but each time I must edit WordPress source code.
Always need to change [_0-9a-zA-Z-] to [\._0-9a-zA-Z-] in the:
* before WP 3.1 version wp-admin/ms-edit.php 149 line
* in WP 3.1 tested version wp-admin/network/site-new.php 37 line
if ( ! preg_match( '/(--)/', $blog['domain'] ) && preg_match( '|^([a-zA-Z0-9-])+$|', $blog['domain'] ) )
No problems were found with used plugins.