The listserv model is outdated in my opinion. It is the ancestor of the modern web forum. However, I can see one advantage being able to follow the posts if you don't have access to a conventional web browser, or you're on a lightweight handheld device and want just text.
There is no way to do that with our current version of the forum software without heavily modifying it. I've only got a certain amount of time to devote to this as it is, and I would like to dedicate that time to more features, as well as new filtering methods for Assholes.
RSS though is something we can work on. My current feed is generated with a fairly simple tool that is designed to just list recent topics. I can look into generating another feed type though that is more comprehensive and includes post message text.