Discourse started as an experiment and the IT team is doing an awesome work. I have the feeling that many Mozillians see this Discourse instance as beta, waiting to see how this experiment will work out.
I think it would make sense to move this instance under a more prominent (sub)domain. Something like: community.mozilla.org or discuss.mozilla.org. You get the point. I know that moving it under mozilla.org may have some legal implications we should consider, but it would also be a good opportunity to have a fully volunteer IT effort under mozilla.org.