The sooner the app store model is broken down for ios devices - the better. People should be able to decide what to run on their devices (and unlike consoles phones are not sold at a loss) and it will also solve the discoverability problem.
the nvidia shield store for games was pretty solid when it was around
I'm not sure how I'd rate the quality of the amazon app store but they did have cool features that let you trial an app in your browser
in all honestly with these two stores owning the entire us market there's never going to be much iteration or innovation.. even something simple like a ios version of itch.io would be fantastic
