For the first time in Asia, skip KL. Maybe just take in Chiang Mai for three days instead.

As suggested, you might consider including Angkor, although Air Asia only flies to Phnom Penh.

A week is a long time in Phuket unless you are a diver, IMO.

How about four days in Bangkok, four days in Phuket, three days in Chiang Mai, four days in Cambodia and three days in Hong Kong?