Currently Street names cannot be searched for. For example Scotts Road and Mangatarere Valley Road are used to access the Tararuas. But you can't find them to plan your drive to the road end.
I suggestion that street names be added to the search, but optionally, so you might have to click a box to include street names into the search.

I was just thinking for this online researching map to make things more interesting in a local and sub-national aspect. And that is to add boundary lines for every territorial unit level within the nation of New Zealand: from regional councils to territorial authorities to wards to even area unit-level divisions (either suburbs & towns & neighborhoods on urban areas or communities & localities & settlements & villages on rural areas). Any thoughts?

show the depths within the lake itself

Northing and Eastings displayed on the printed map

For some reason the map is rotated -2 degrees from vertical

Could you please add marine charts to your topo maps options
This would make it a lot easier for me to plan shore diving and fishing trips and will add to your user base.

An app where we can nominate a height above sea level and create for instance a map of NZ from say 250 meters or 500 metres.

Just as we make the Topo50 / 1:50,000 downloads available, make Topo250 / 1:250,000 map sheets and Garmin Custom Map / KMZ downloads available.

When printing a map, add grid numbers to the sides to make them easier to use.

The ability to upload GPX, KML & KMZ overlay files directly to the service for displaying over the topo map without needing to self-host using a 3rd party service like Dropbox.

This will make sharing tracks and other overlay information on the topo maps easier.

Adding the magnetic compass cross could be very useful either there by default or as an option

Add DOC hunting areas to the map so they can be searched for and shown on the map.

Run another "hunt" to win prizes much like the Xmas Pressie Hunt ran in 2012 - http://nztopomap.tumblr.com/post/35049851139/christmas-pressie-hunt

Make a WordPress plugin available to allow embedded topo maps to easily be added to WordPress pages.

Remember the last location and zoom I was viewing on the map for next time I visit the service.

Add LOC file support to make the maps easier to use for geocaching. Needs to be supported in the same way as GPX, KML & KMZ files.

When using the transparency control to compare the topo map against satellite imagery the ability to zoom in further would be handy as the satellite imagery has more detail available.