Maybe the meta Community♦ user should be trained not to bump meta questions with certain tags?
According to On Meta, have Community ignore posts with a [status-*] tag when bumping, this is status-bydesign that Community bumps questions even being marked as status-completed.
completed stuff should have at least one answer with an upvote, so we know our "completion" wasn't total B.S. that everyone hates.
It is not a bug. I upvoted the answer shortly after the question was bumped (about 8 minutes after if I remember right). I noticed the status-completed tag and opened the question hoping to find something worth voting up to keep it from being bumped again. Sure enough, I found Jin's answer very upvotable.
I don't have a strong opinion on your last suggestion, but I think that in most cases where the status-completed tag applies, if an upvoted answer doesn't already exist, one could be added saying what the change/fix was, so that someone like me could happily upvote. I suspect that this is rare enough to not require changing the software. Actually, checking the status-completed questions in the unanswered list, it looks like there are a few more answers worth upvoting (soon to no longer be in the unanswered list).
I could be wrong (and if so please correct me), but my experience seems to suggest that questions without any answers at all aren't bumped; only the ones with at least one answer and none with positive vote count. If this were true, then it would always be possible to stop the bumping from occurring again by simply upvoting (unless there is something about the answer to make upvoting seem like a bad idea).