I do agree with this. If you are fine just hanging out at the pool for a day or two then 5 is fine, it isn't the worst place in the world to spend a few extra days. If you expect to stay busy 4 nights is probably max.
As for Amanwana, yes it isn't an easy place to get to period, but especially from Yogya. Bali is the easy transfer from Jiwo and why many combine the two, so you are talking 2 or more flights to get anywhere interesting no matter what.
Fly to DPS from YIA or SOC, spend 1 night somewhere close to the airport (plenty of good options within 30 mins, including Nusa Villas which can be booked as a single villa now), and then off to Wana. It isn't perfect but nothing is going to be in this scenario.
Thanks for the advice! Wana appears to offer limited dates for individual bookings, but we probably can make it work. How long would you recommend to stay there?
Do you think it's still a good idea to go there if we don't dive? We snorkel ...