Probably have your hands full with 3.4, but I'd love this as well. It allows us to expand the functionality of Cloudron to fill any holes in our deployment requirements, and eases the pressure on you guys to get apps out.
Please note that existing Cloudrons will not use wildcard certs automatically. You have to go to domains -> edit the domain -> advanced -> Choose wildcard provider. New apps will then start using a wildcard cert automatically. Existing apps will start using wildcard certs once the existing ones expire. If you are impatient, you can just click on 'configure' of an existing app and click save to get a wildcard cert.
Also, wildcard certs only work with programmable DNS.
Finally, for new Cloudrons, wildcard is the default.