I don't believe this would be a good idea. Let's say I'm playing solo or teams of two. My neighbours both left after the game starts, the egg is sitll there afaik, so I go to mid straight away (or build to their island to get the egg points). Later on a player joins on the island next to me and can quickly break my egg. This can also be an argument when playing To4 if the team next to you only has 1 player you'd most likely go to mid.
The reason this works on Blockwars is because there will always be 2 teams fighting each other, it's especially nice as this will potentially keep games filled and thus even.