14 months ago, an Unearthed Arcana supplement was published that discussed how the ranger described in the Player's Handbook was under powered. These rules reimagined the ranger's abilities, and suggested that an official version would be released later.
Finally, we come to implementation. If this iteration of the ranger, or a future revision of it, grades high enough, our plan is to present it as a revised ranger in a future D&D sourcebook.
Does that Sourcebook exist yet? If not, have the devs given an update or told us their intentions?
Best Answer
It won't be released as a fully revised class, only maybe as a set of alternative class features
Rules designer Jeremy Crawford originally indicated in an August 2017 tweet that the UA revised ranger would require revisions before being published:
Crawford later clarified in an unofficial Twitter exchange in October 2017:
However, Jeremy Crawford did eventually make it clear in this July 2018 Twitter exchange that any work on the UA revised ranger as a wholesale revision of the class was no longer occurring, and that at best it was a "possibility" that some alternative class features for the ranger would be released:
In short: the revised ranger won't be published as a whole separate class. At most, it'll be a set of alternate class features, allowing players to swap out a particular PHB ranger feature for an alternate one - but the designers plan to do more research before they actually decide to do that.
As of November 2019, this is being playtested in UA
On November 4, 2019, Wizards of the Coast released Unearthed Arcana: Class Feature Variants for playtesting. This UA includes variant class features for every class - including the ranger - that replace or enhance existing features.
As summarized on page 2 of the document, the ranger gains replacements or enhancements for nearly all of its base class features from 1st to 3rd level, as well as a replacement for its 10th-level feature, and an enhancement of one of the Beast Master ranger archetype's features:
The 1st-level Natural Explorer feature (gives benefits from chosen favored terrain), as well as its 6th- and 10th-level improvements (choose additional favored terrains), are replaced with the Deft Explorer feature, a series of 3 benefits that you can choose one of at each of those same 3 levels, in any order:
The 1st-level Favored Enemy feature, as well as its 6th- and 14th-level improvements (choose additional favored enemy types), are all replaced with the Favored Foe feature (learn hunter's mark without counting against your number of known spells, and cast it without expending a spell slot or requiring concentration, a number of times equal to Wis mod).
Rangers alone gain the 2nd-level Fighting Style option Druidic Warrior (learn 2 druid cantrips that count as ranger spells for you, and you can swap them on level-up), in addition to the new Fighting Style options added by the UA for all classes with the feature.
The UA adds a few spells to the ranger spell list (a few, like entangle and dominate beast, seem like they should already have been on it).
The 2nd-level Spellcasting feature gains 2 other enhancements. Spell Versatility (which several other "known" spellcasters get in the same UA) lets them swap one known spell for a new one of the same level on a long rest. Spellcasting Focus, obviously, lets them use a druidic focus in place of material components.
The 3rd-level Primeval Awareness feature (waste a spell slot to find out that an unknown number of a known type of creature is at an unknown location within 1 mile, or 6 miles in favored terrain) is replaced by Primal Awareness (learn 1-2 specified spells at 3rd, 5th, 9th, 14th, and 17th ranger level, and cast each of them once per long rest without expending a spell slot).
The 10th-level Hide in Plain Sight feature (spend a minute to camouflage yourself and then press yourself against a surface to get a +10 to Stealth checks until you move/take an action) is replaced by the much simpler Fade Away feature (use a bonus action to turn invisible until the start of your next turn, once per short or long rest).
Finally, the Beast Master ranger gains 2 additional options for their 3rd-level Ranger's Companion feature: "a primal beast known as a Beast of the Air or a Beast of the Earth". Their statblocks are too long to summarize here.
Feedback surveys have already gone out for this UA. It remains to be seen whether some or all of this content will end up being published (and how it will be changed if it is published), but this does seem to reflect what Crawford meant in earlier statements by "alternate class features".