I agree that overuse, or ill-considered placement of teleporters can be very confusing. However, some people like that sort of mayhem, and I might actually play a map like that occasionally (for a change of pace).
The teleporter is a very versatile tool and opens up all sorts of possibilities (if used with intent and restraint).
And as far as this game being remotely 'likely'...have you seen the city flying in the air dripping lava? Have you encountered armies consisting of: a hero, a devil, a unicorn, a medusa, and a couple of spiders? Just think about what that would actually look like.
Anyway, gateways to distant lands/other worlds are pretty standard fare in fantasy literature...so it fits the theme just fine.