i say do whatever you can pull off without looking too strange.
the difference in the ratio is that it looks like the map is more or less rotated. you could make a camera rotation that way, by using some "smart" rendering functions. let''s say if you wanted the camera to track the position and direction of one of your agents..
you wouldn''t have to use 3d, but that would require at least some thinking
now that i think about it, that would need alot more graphics. maybe TANS''s book covers some such effect that you can do to a tile, haven''t finished it yet..

//Demiurge
Make something idiot proof, and someone will make a better idiot..