I just think it needs more bright white trim around the windows and the fence painted also white. Going round to the back addition, I would paint the timber boards the color of the stucco, trim white and get some great deck furniture and lighting.

Well that is one rule that begs to be broken! I think a matte silver roof would look good....not weird at all. I don't think the house below looks "weird."

I don't know how hot it gets in Auckland in summer (I've only ever been to NZ in winter!) but if it gets hot, then go for a pale colour. Dark roofs should be kept for cold places!

Personally , I think that to give advice , you'd need to supply more information -- what the neighbourhood is like , your favourite colours , the plants in your garden , and the likes . I quite like the colours there , but I'd do the front door , the gutters , the window sills and those cap pieces up the pillar supports in an orange or teal or red or similar to add some Wow and excitement , but thats just me .