All the advice sounds great, I'll throw in another pension to consider, because we love it, we love the owner/operator, he will take you pretty much wherever you want to go too, and the bungalows are beautiful (there are 5, 3 beach, 2 garden and the garden have lap pools) He is close to Avatoru, but all dive places will pick you up.
I second the pearls advice, or third it, as well!
Fakarava has a very nice place, it is their equivalent of resort I guess, but much smaller. The bungalows on the beach have AC, and frankly you need it because there is little breeze (due to placement and trees between ocean side and lagoon side there) and sunset, it gets hot. It is called Havaiki,a nd it is also a small working pearl farm.
If you make it to Fakarava sometime, it is a great option.
Breakfast and Dinner are included, and dinner has never disappointed. There, you sit at your own tables. (at tevahine dream, rangiroa, meals are at a round family style table in the main lounge area, and it's a pretty neat experience! people from all over the globe, with a heavy contingent of french of c ourse. Food is always excellent, and far too much to eat)
Fakarava is a beautiful atoll, very clean, the village on the north pass is very quaint and pretty, people friendly, and there is a nice snack shop that sits on the lagoon which is about a 5 minute bike ride from Havaiki. We go there often for the grilled mahi and/or mahi burger. There's also a snack shop that is on Havaiki, but it is more pricey and we like the ambience of the snack shop in the village. We also discovered that one of the markets sells ice (they freeze bottled waters) and so we got to have tahiti drink on ice a couple of days there. There are refrigerators in the rooms, but they are not cold, more like a cooler. The refrigerators in the bungalows in Rangiroa are cold,and actually have a small freezer portion. Very nice to have cold water!
Oh, Havaiki has a water cooler so you don't have to buy much of your own water, and Tevahine Dream gives water at breakfast and dinner as well.
Also, at Havaiki water shoes are not necessary in the lagoon, it is soft bottom and not full of crushed coral/rocks like you will find in Rangiroa. In Rangiroa, we usually go through a pair of water shoes by the time we leave. So we always bring a new pair along (only about 10-15 so no big deal)
Diving, we have never found it repetitive although yes, you are the same location (pass diving/near the pass/just outside or inside the pass, etc) each dive has been unique, every time.
Both in Rangiroa and Fakarava. I also don't like moving around if we are not there at least 5 nights, typically more than that, because you do lose a day traveling.