I wrote an article about DX12 for PC Gamer. It discusses the differences between high-level and low-level graphics APIs and what that means for gaming. It also features some insight gained from talking to Dan Baker at Oxide games about a few related topics, which was a big help.
I went a bit wild in terms of technical detail in the middle section of it, but it could be up your alley if you read my blog (and hopefully also interest some PC Gamer visitors).