As you know, core's Trigger module is en route being deprecated, and "Rules is now the canonical method to create triggered responses to actions". (See http://drupal.org/project/trigger.)

Given that Maestro has some real promise, for longevity's sake it will have to be ported away from its dependency on Trigger to full use of Rules.

Perhaps this should be the central focus of 7.x-2.x development.