Micah Sweet
Level Up & OSR Enthusiast
They were never going to make a DMG2 for 5e. Players wouldn't have been incentivized to buy it, and WotC won't produce a book that only a segment of their fan base would find useful.Perhaps like 4e required two DMGs to get their message across and their attempt to explain how Skill Challenges actually work (which from my point of view - failed), a further 5e DMG may have satisfied your needs.
EDIT: I do think from what I have seen of the latest UA that their layout style and thought process seems to align closer to the indie games such as Dungeon World and such, specifically with regards to actions that may be taken by characters.