If a Metro system is to be embarked upon, you may as well just hold off until 1.9. I personally don't like the warping system, but I find Runecraft more practical and yet it fits in with the game. In order to teleport you have to create a waypoint(where you teleport to) and a teleporter.

Minetracks sound cool, but they can be a pain in the ass, especially over very long distances.

I'd rather have runecraft over /tp, but runecraft + metro could be cool.