I understand your point but there'd be no need for a spawn camping rule and the spawn shooting rule should stay. What I mean is instead of the randomly generated area around spawn with some random buildings, the whole area is built upon, roads, slopes, some buildings. Instead of some hills and slopes, the place would be built with PvP in mind, maybe housing a nether portal, end portal, shops, other stuff.
Like I said, most PvP DOES happen around spawn, so if the area around spawn is built like one massive arena it'd work well. It'd at least be better as the warzone will be extended.
The area shouldn't be like a maze, just improved for PvP. Implementing any kind of spawn camping rule saps PvP because people have to think 'Am I killing TOO much?' and that sucks, you don't want to have to worry about getting in trouble for killing someone a lot on a PvP server. They can always just jump out of the other side and run. I do understand your reasoning though.
@Velo The warzone around spawn will all be changed, so, yeah, they'd have to walk through it :>