The hints & suggestions made my Olisch make a lot of sense to me.

I'd add to that:

BKK:
Not so sure if it's the ultimate honeymoon destination.
If you've been there, you know if you'll be comfortable.
For me, it would rather be my ideal shopping and maybe sightseeing
destination. So maybe rather a last stop to come back to civilization
after enjoying island life and before going home.

Chiang Mai:
Even if you are SPG Plat, I'd not stay at the Le Merdien. It's just a big yellow tower which could be in the middle of just about any noisy Town. It's nice and cool and modern and everything, but it's just an ordinary contemporary hotel. I have to admit that I haven't ever made it further than the lobby.

It's your honeymoon, so I'd use the money you may save by skipping Tokyo and go for one of the really special places, like the Mandarin Oriental Dhara Dhevi or maybe the Four Seasons.
There should at least be a 3 for 2 deal available in the low season, which makes it a little bit easier to swallow the price.

I'd highly recommend the Oriental as well for the delicious food and service in very pleasant settings, both Thai ("The Grand Lanna") or Mediterranean. ("Akaligo").