Hmm,
Not seeing anything obvious that would serve as a great chance to do something here, in the current version. However, I agree that some hooks and filters for this type of thing would be a great addition to the plugin, so I will be filing enhancement issues for it.
Just in case you’re able to spot something I’m not at the moment, by all means browse through the core code. I know we have a ctct_process_form jQuery action in ctct-plugin-frontend.js, that you cold maybe do something with, regarding your own AJAX callbacks from the PHP side.
Marking as resolved for the time being. If @garrettcgoeppinger comes back with new details or an update, we’ll resume from there.