Something I'd really like to see in Campaign Monitor is the ability to apply filters to reports.
e.g. A list has a custom field for Gender and a client would like to compare the results for male and female subscribers.
To my knowledge, the only way we could really to do this at the moment would be to create segments and send a separate campaign for each. But that isn't a particularly glamorous solution, especially if we wanted to compare multiple metrics, or if the metric has more than just two options.
Has this been suggested before? I couldn't find anything but that was partially because a search for 'Campaign Monitor Report Filter' just returned queries about spam filters!
Thanks for taking the time to post your suggestion, I've added a vote for you in our system for more robust, subscriber-centric reporting features. Have a great weekend :)