There are now various captcha solutions that work with the Joomla core. I would like to see an option in the Anti-Spam settings that allows me to choose my chosen Captcha option that has been set in Global Configuration. This is a good solution for you because you don't have to try to accommodate requests for a dozen different captcha solutions. Instead, just route this through the chosen Joomla captcha plugin. An option such as "Use default Joomla captcha - Yes/No" would do the job.

It might be my old age, but reCaptcha seems to be getting worse. I'd love to try NoCaptcha.