We have always been very, very conservative when it comes to contacting users by email. Over time, users have suggested sending emails about virtually any type of activity they might possibly be interested in. I hate it when other services send me a constant stream of emails simply because I dared once show interest in something on their system. It becomes very invasive fast.
Frankly, that system message was little more than an after thought — a way to tell users, "A 'Gaming Recommendation' proposal might not be the best use of Stack Exchange. Why don't you try this better solution instead?" It wasn't some cage-rattling event meant to change the entire course of the proposal that everyone must simply be notified about.
Jeff already tweeted about it. Surely you've already had you hand in promoting its use. Beyond that, it didn't feel very grand-announcement-worthy.
Area 51 was envisioned to be a bit more of an iterative process. Users should be checking back periodically to see such developments. But, admittedly, it is still much of a set-it-and-forget-it affair. The up-and-coming meta discussions that are being added to Area 51 might be a first step to bringing interested parties back into the process.
We simply don't want to take a step back into the 1980s by making email the go-to way of contacting users.