I feel that wildcards would be a very good idea on the basis of security.
I have been watching the project since its inception and believe the concept is crucial in todays modern world.
I have started using this service for my personal domain which I use as a hobby for development to host my personal email and own cloud storage.
Now that I have explained the back ground, the reason I believe that this is beneficial for security is;
My sub-domains are not publicly listed which hide them from the outside world but because they have to be specified in the cert anyone can open the cert and see what I am protecting.
This allows for new attacks to take place where as a wildcard would keep them hidden from those who wish to cause harm.
Thanks for your consideration,