my last Android dev job was two years ago, I try my best to give you some feedback. Lets start with expectations. I expect that tasks performed by the majority of Android developers are actively supported by Google and are as easy as possible, with as few code lines as possible.
# REST - A lot of apps consume REST APIs. REST is almost the standard way to communicate with the outside world. Therefor the Android framework should include APIs to consume and send REST-requests and parse JSON easily (a support-rest lib would be nice, too). Depending for one of the main use-cases on third-party software is not okay.
# SQLite - Android really needs a support-sqlite library. Right now you have to use SQL features of the lowest supported api level, which means you are stuck in the past (if you want to stick with the default).
# Permissions - https://developer.android.com/training/permissions/requestin... - Handling permissions for older and new devices is a nightmare. I would expect to be able to declare the need for a certain permissions in – lets say 10 seconds – but figuring out how to get the permission bits right took fare longer (maybe 1 hour) and if I had to do it again, it would probably need again one hour. Instead of half a screen of boilerplate code and an activity-callback like onRequestPermissionsResult(), it would be nice if there where a PremissionBuilder, which would allow to easily setup permissions (spreading code all over the activity to do a basic thing is not that great).
# Cache - https://developer.android.com/topic/performance/graphics/cac... - Almost every dev needs & should cache data to improve app responsiveness and use the network less... To my knowledge there is no easy >>general<< caching mechanism in Android (maybe support-cache in the future ??). There is LruCache, but using it means almost writing all caching stuff yourself. Okay, there is Glide for images, which should probably be part of Android, but beside of that, void :). What would I expect? An API which lets you declare how something should be fetched, how many bytes/how long it should be in memory and if and how it should be saved to disk. Caching is such a general problem, I wonder why it hasn't been solved long time ago (we don't need the perfect solution, we need a solution – since it's such a common problem I don't feel like its my job as app-dev to solve it, I can, but I shouldn't do it).
# Effects/Transitions - During my Android years creating custom effects was very complicated and frustrating. Opening Qt Quick Designer for the first time and seeing how easy it is there, I was kind of shocked.
# Outdated information/blog posts - When researching a topic it is very easy to come along outdated knowledge. This is a real problem, since you don't know what you don't know. Sometimes I did things, just to learn later that there is a newer/better Android API. Since Google has not much control over it, I would suggest that Google keeps track of their own blog posts/articles and move them after some time into an archive or put a big (orange) banner on top of them, telling the reader that the content is outdated. Managing the produced textual output might be boring, but it seems to be necessary. I don't know if any company has ever done something like this... but, it would be great.
# Android takes up too much time & attention - Its difficult to describe the cause, but overall I felt like I did fight way too much with the framework, even after years of experience with it. I never had the time to care about things like battery saving APIs and such. It's sad and I wish I could have spend some more time following best-practices. Overall I think Android has to become simpler, I assume most people don't spend a huge amount of time learning all the bits of a given topic, they just want to get things done. Fare too often you have to know hell of a lot of things in Android, write a lot of code, like for RecyclerView with a custom Adapter (most people probably need a custom adapter, even the example is already cluttered) https://developer.android.com/training/material/lists-cards.... ... it's just too much code for such basic functionality.
# Android Studio UI ... has too many buttons, even for things like copy & paste, back & forward and may other buttons, I doubt those are use that often (we are experts, not computer novices). I know I can customize the UI, but still I wish the default was less overloaded :)
I acknowledge the huge amount of work Google did to make Android better over the years and things got really better. The introduction of the support library was stellar, thanks! </brain-dump>