Specify external mail server/relay
Are you going to implement the ability for users to specify their own SMTP server? This is a huge negative for Wave as mail gets stuck in spam filters and this will only get worse and worse as more malicious mail circulates, and also clients don't like seeing mail come from some long random Wave email address, I've literally had calls from clients saying I've been hacked because of this.
I think of it as a foundational feature that should be included. Can you share if you feel the same way or if there are/aren't plans to incorporate this? I think this would be a huge factor in retaining your own clients/Wave users and perhaps capturing those who turn away due to something like this (which is a major in my opinion).