Well I'm no expert on FP, but I know a lot of people go for 7-14 days. It probably depends on what type of vacationer you are, and how many islands you go to. The flight arrival/take off times are pretty bad, and it is easy to lose a day or two in the process, plus with jet lag it'll kill another day or so. You could easily do 1 day in Tahiti, 5-6 days in Moorea and 5-6 days in Bora Bora, or even add another island.

I think if your idea of a vacation is hitting up 3 countries in 2 weeks, then probably 2 weeks in FP is too long. If you're fine chilling at 1 resort for a week relaxing, obviously this is the perfect vacation.