Despite having an app simply ripe for multitasking as users pull up extra info related to the books they're reading, Amazon's Kindle app is just now delivering support for Android's split-screen viewing feature. It added support for split view on the iPad back in March, but with this update all of your Android 7.0 (and higher) devices should be ready to go.
Also noted in the update is the tease of a Notification Center which should bring all the "fun" of constant updates. It isn't quite live yet, but hopefully Amazon can find a way to let user's know their favorite author has a new book out without increasing our levels of annoyance. It's due to start working "in the next few weeks."