MikeB4, sadly, I don't think your enthusiasm for WP is enough to save the platform.
For several years now I have been keen to trial WP as I like the OS in principle. But I can't justify switching from android as the app void is just too great. And the sad thing is that as time passes, things don't get more encouraging for WP, they get more dim. Let's be honest, WP is dying a death of a thousand cuts.
I agree fully with an earlier post - WP Surface is last chance saloon (but I'm not holding my breath)!
Which apps are missing? I really don't notice anything beyond bank apps (except ASB).
Kiwibank (I know you mentioned bank apps, but they are such an useful daily app)
Google apps like Maps, Gmail, Chrome, Chromecast, Hangouts (not on WP, but all of which are available for iphone users - so not exclusive to android).
Diving into my app drawer, starting at A:
(I stopped after the B's as the list above is already a too great an app void for me to consider trialing).