Webhosts who allow their users to access ImageMagick but disable exec just have no idea how to run a webserver. Imo we should not care too much about silly webserver setups (just because that's not our business). Instead, I'm planning to add a check into the installer and config that only will allow a user to change the image library if a check has been performed if the settings the user has chosen actually work.
However, others may have a different opinion on this.
Moving this thread from support to feature requests.