The December weather is actually warm enough to sit on the beach, but most people who come to Dubai tend to just relax and do a lot of shopping at one of the enormous and modern malls here. The restaurant scene is very interesting as well, and you can eat cheaply if you follow the local workers, or go to one of the hotel restaurants and get world-class cuisine.

Bali is wonderful, or at least parts of it are, but they now have a volcano issue and those flights are very long and never cheap. Machu Picchu is incredible, but it’s a place you visit for half a day or so, and they actually have their rainy season at the end of the year, so it’s actually not one of the better times to go. Actually, you might consider a trip to Argentina, which is warm that time of year, though rarely scorching. Buenos Aires is a wonderful city that is pretty good value now, and you can also visit the Mendoza wine region and Iguazu Falls and Bariloche, which are all even a bit cheaper than Buenos Aires.
Without knowing more about your interests, my top suggestion would be to focus on Sydney and Melbourne and the areas around both. The Blue Mountains near Sydney are also nice for a couple days or so. The main challenge you’d have in seeing a lot of Australia is that it’s all so spread out. You can hire a car for Melbourne and Sydney and that whole area, but it’s better to fly to get to Uluru (near Alice Springs) or Brisbane or Cairns/Great Barrier Reef or Perth. You’d be driving for days in between those places if you started from the southeast area where most people live.
I too am a planner, which is how I got involved in this, and so I totally understand your motivation. I think your plan sounds quite good. The weather in the places you are planning is actually fairly mild, and none of them are too far north. For some of us it’s easy to forget how far north parts of Europe are, and in those areas it’s not so much the cold but the fact that the sun rises at 10am and sets at 3pm that time of the year.
I need some help planning my honeymoon which will be around the last week of November. We plan to spend anywhere from 9-12 days. We aren’t big beach sitters(a day or two by the beach would be enough). I love culture and buildings and my fiance is shopping and nature. I always tend to lean towards going back to Europe but the weather in late decmenber is kind of a detourant. One big issue is my fiance vetos anywhere that is on the CDC’s list of Zika virus areas. We were going to go to Argentina and Chile, but Argentina is now on the list. i’ve considered is still doing Chile(risk is when will it join the rest of south and central america on the zika list), Morocco, and i always think italy is a good option.
If you have a budget that allows at least US$300 per night, you should be able to rent a nice condo in Hawaii. If you haven’t been there before, it’s worth knowing that each of the 4 main tourist islands is quite different from each other, and only Oahu has an urban center that should probably be avoided. You’ll want to rent a car as well, as getting around is difficult without one.
Since flights to Mexico City from the US and Canada are usually quite cheap this time of year as well, this could be a perfect short cultural holiday. This city has great shopping, dining, and nightlife, and the central historic and tourist districts are far safer than most people would expect. There are ruins just out of town as well, so a bit of everything is available.