By now, page speed has been improved dramatically. Web Page Test and Google PageSpeed were very useful resources to improve this aspect of the site.
As a long-time and extensive user of the wonderful mailnull service, I really wanted to implement the same functionality on the new messaging platform. It is now done. Users can simply create new email addresses by mentioning one to someone or on a web form. The actual inbox for it is created as the first message is received. The added benefit to all other “disposable email address” services is that a dialog can be had through that address. Meaning that when I receive a message from that shady webshop I bought a pair of shoes from, I can answer but still remain behind the (“disposable”) email address I had submitted there. Plus, of course, I can choose to levy a postage on the new address. Be it right away, or once I am fed up with the messages I receive.