A lot of the rationale behind some of the AOW choices lies in the location. I just worked with an AOW student here in Colorado. When we talked about what he wanted to do for his elective dives, he mentioned videography and photography. I did have a good laugh about doing those classes in 5 foot of visibility. We could have enjoyed looking at his GoPRo video showing a half hour of a the greenish haze of the algae bloom. Fish identification is another good one--hope you enjoy thinking, "Yep, looks like another crawfish." Boat diver (which, BTW, has a lot of information in it that goes well beyond being a passenger on a typical dive boat) is another non-starter.
One I like to include in the mix is altitude diver. That may seem odd because, like nitrox certification, everything involved with that dive is done on the shore. Once in the water, there is really nothing special to do. I like that because it gives me the freedom to do what I like to make the student a better diver. We can get all the altitude academics out of the way and then plan a dive that really helps the student learn to dive. It allows me extra freedom to do what I like to do with an AOW dive, which is to plan a sequence that builds skills throughout. For example, once we have done the navigation dive, we will have some navigation to do on every subsequent dive. After Peak Performance Buoyancy, we will work on those skills on every dive thereafter. A student can really learn a lot in a well-planned and coordinated 5 dive sequence.