Certainly Kendrick Lamar, for example. To Pimp a Butterfly has a few radio-friendly song, but overall, it's an incredibly dark and experimental album, back to jazzy and soul roots of hip-hop — and don't forget the whole concept thing.
To Pimp a Butterfly is an excellent example of a good album. I find it difficult to listen to most of the individual tracks, but the thing as a whole is incredible.
I don't know. This is by no means a "back in my day" complaint, but I miss the concept of a giant, stadium filling band deciding to throw caution to the wind and releasing something effectively "unsellable" to the public at large.
The Smashing Pumpkins did it with Adore, and Radiohead did it with Kid A (although Radiohead succeeded sending that album to the top of the charts by having at least one radio-friendly song on there). Some other bands I'm forgetting now.
The only "giant" artists I can of who are flirting with experimentation are... Kanye? Maybe Drake.