Scaling any kind of cluster membership protocol beyond single digit thousands is currently a hard problem with Cluster Membership protocols we have today. Even in the single digit thousands 1k-5k you are going to have to have a team of folks that meticulously attend to your ETCD/ZK/cluster membership service.

So we started running an experiment on my team a couple of months ago where design docs are checked into a repo and reviewed as a PR instead of done in a word doc and stored on a sharepoint or wiki. This was inspired by @github process, and I have to say I love it. Its really easy to see what comments were made and track that they are addressed, and which docs are a work in progress vs approved. If its in master it is approved, otherwise still in progress.