Review: Luxury South Pacific Tour, Australia, New Zealand, Sydney, Melbourne, Queenstown, Auckland, Milford Sound, Phillips Island

I'd drop one Melbourne day and skip Great Ocean Road bus tour. Lots of time sitting in a vehicle. Views are great but too much travel time between. I'd extend my stay at Longitude 131 by that extra day, add an extra hike, and maybe a flight tour of the Red Center.
I'd choose a different reef tour closer to shore with more colorful coral. Quicksilver was a first class experience but lots of travel time to the outer reef reduces time in the water.
I'd skip stay in Franz Josef and take Tranz Alpine train round trip from Christchurch. Spend that extra day or two in Queenstown, visiting glaciers from there rather than Franz Josef, if glaciers are on the plan.