I like the straights, but do not agree with there being 2 ways to get to stewart Island because as a new zealander i know the only way to get there is via Invercargill.
I think your onto a winner with the airports.
I think the way to get around the problem of playability being a long island as everyone keeps telling you might be to expand on the airport idea. i'm not sure if you know newzealand well but some airports only fly to surtain places and so on, eg wanaka has an airport but u can usually have to go via Christchurch etc.
Maybe think outside the square and come up with new formulas rather than the same old tried and true ones. eg, sea currents and the natural disasters as someone else said. Or the sate highway 1 which goes down the middle of nz
I dunno really just an ideas.
Youve prob seen this but you called lower west coast lower east coast.
Well good luck and just remember sometimes too many ideas can be negitive for the creative process and don't take them all onboard.

(This said after i have bombarded you with many lol)
