The settlement size limit does not increase when new settlers arive. It's unplayable without a patch.

And the settlement junk gate does not lock out enemies. Why isn't it possible to assign a settler to bar it and keep it closed from obvious enemies? Pretty boring.

For example the settlement area limits displayed by green walls could expand with the number of settlers, so that it won't be possible to fence the whole settlement before a certain amount of settlers ...

It would also be playfun if settlement constructions were only possible by assigning more settlers to construct so it would take some time

Apparently it has been confirmed by several other players that the settlement size limit can be increased simply by dropping junk on ground in a settlement and then scraping it, because when playing otherwise putting stuff unscraqed in the workbench and then just building stuff and thereby letting the game itself scraqe items shared in the workbench, then the settlement could only be tiny before the settlement size limit was reached!

When you patch this, perhaps you could also make it easier to build all those wall around settlements again, which is a very slow and difficult task, since they don't quite fit. And also make raids on settlements unpredictable dynamics, because it would be boring to build defenses knowing simply from an online tutorial that there won't be any other attacks than bla bla...

Edit: Reference: http://www.gamesas.com/topic/1549440-the-settlement-building-limit-is-a-joke/page-2

In place of wall or fences, build fence posts. What I do is use the fence posts on uneven ground and the fences on flat ground.

Huh. That must explain why I never got close to a limit - that's how I was doing all of my scrapping.

How to recreate the bug - reference: https://www.youtube.com/watch?v=TszQTVO6KpU

Edit