Seems like a good improvement. Tested form rules and both regular / adv search flows. However, I'm seeing what I think is a regression related to mass mailings from advanced search. If you start this way, then Save and Continue Later ... when you continue - the 'hidden group' is visible in the "Include Group(s)" set. I need to test in 4.4 to verify if this is a pre-existing bug.
https://github.com/civicrm/civicrm-core/pull/2455