As for Amazon, they're pretty good with generating updates. For a new product it's no too surprising to not have all developers on-board until the public release. It's inconvenient, sure, to have old versions, but that can be solved with updates.
Personally I don't really want another set top box with it's own remote. I really do prefer the tablet-controlled, network-sourced Chromecast approach.
It's a very interesting time to be using AV tech right now. Finally, a lot of the vendors are getting out of their own way and providing a better range of interoperability.