Hi, I just got back from Wakatobi in September. I stayed in Premium Bungalow #7 (one of the sunset facing ones) and a friend of mine stayed in Beach Bungalow #21 ( I guess that would be a south facing one). If I went back I would probably save my money and book a Beach Bungalow or maybe even a Garden One (you can still see the water from those). The breeze was really nice around those, our Bungalow area was EXTREMELY hot from the sun and dead air! Also, the Premium Beach Bungalows, at least the ones South of the longhouse where I was, are behind a bunch of palm trees and the main path, so you're pretty far back from the water - maybe just as much as the other Garden ones actually.
As for the sunsets, I was pretty much on the jetty bar every night at sunset with my bintangs, so it didn't really matter that we could see it from our room

It was nice that the room was so close to the restaurant and the gear room and longhouse and everything though, so if you'd prefer to only be a 30 second walk instead of - say - an 8 minute walk, that is an advantage. As for your question about walking back to the far cabins on the beach at night - you really can't because when the tide is in, the water basically comes right up to the seawall.
I hope this helped, feel free to PM me if you want!
I hope you have a great time, I am jealous! I want to go back!