Sometimes, I find that before I post my edit, someone already has edited the post.

Can't we make a system like this:

Without the Feature

So, lets say User A started editing X post, and User B barges in while User A is editing. User A sends edit, few seconds later User B sends edit, which is less good. Good edit by user A lost

With the Feature

User A started editing X post, and User B barges in while User A is editing. Warning shown.. User B checks out new edit after A has finished posting. User A&B gusta.