When you post an edit, anyone with an open window/tab to that post gets notified (Via a "an edit has been made to this post. Click here to refresh" header on that post).
If you edited a post, while someone else is still editing it, one of two things will happen when that other users submits:
- If your edit was more substantial than his (You made more changes than he did), his edit will be rejected, and he will need to review your edit before making his own.
- If his edit was more substantial than yours (He made more changed than you did), his edit will be approved and override yours, because it changed more things.
On the topic of suggested edits, you have the ability to see and approve/reject suggested edits to your own posts, even if you don't yet have 2000 reputation. Your vote is also binding, if you approve the edit, it will be approved immediately, regardless of what others have voted (unless it was already approved/rejected).
Based on all of the above, I argue the situation you describe is an edge case, such that doesn't justify a new feature or a change in the system.