I think DevOps suffers from the issue that there aren't really many power users who are sticking around and using the site and participating in chat and meta. The "middle class" of users who generally want to influence the direction of the site and are eager to participate seems smaller here to me.
Of course I'm perfectly guilty myself, being active in the beta but my recent activity here as dropped off a lot. I took a look through the recently answered questions though, and I noticed that a surprising amount of questions were being answered by new or low-rep users rather than seeing the same few users come up again and again. In some ways that's great; you're getting a good flow of users to keep the site fresh and healthy.
But... it doesn't look like you have a lot sticking around to keep building the site. I just took a look in /review and handled one—from late June!1 Obviously if people aren't interested (or able) to take part in the community moderation like /review, meta is equally going to suffer. It's all about making people want to take part in the running of this site.
If there are more users in the "middle class" participating, I think naturally there will be more meta activity.
Voting and making sure newer users want to continue participating is one option on the main site to boost activity; one would hope this boosts the number of people visiting meta (if we assume the fraction of people visiting meta is roughly constant, then more users = more meta users!)
Featuring posts to make sure meta is discoverable might be another good idea; both to encourage new users and more established users to use meta more often.
I think you are right to be concerned about having no feedback on meta; it makes community-led site moderation more difficult, but I guess you just have to assume if you're not opposed, then you're trusted to make the right decision.
1: I have no idea why that wasn't invalidated weeks ago by the system; alas it was not, so it's a good talking point anyway.
