For the banner, I'd definitely agree with Minoa's suggestion of having the banner of flags instead of what seems to be the US/Mexican border: I think it is much more inclusive than the wall, and it describes what the world is: a bunch of nations all together, even if they all live in their own little regions.
As for the The world contains x nations and regions text, I would much prefer option #2: it does not really describe anything beyond "The world contains $A nations in $B regions," unlike the WA page where it provides some useful information about what the WA does, and so I think it would be better to not bother including the formatting.
The search bar would be a good idea, especially because it would make it easier to determine if X region exists before using the name for your own planned region.