Are the ranger subclasses from Xanathar's Guide to Everything compatible with the UA revised ranger?

Question

My games use the UA revised ranger (from Unearthed Arcana: The Ranger, Revised) instead of the PHB version of the class. The question did not previously come to mind, because until now my players either chose the Hunter or Beast Master subclasses, both of which have a variant included in the same UA. However, now the question has come up:

Are the ranger archetypes from Xanathar's Guide to Everything compatible with the UA revised ranger base class?

I want to combine the base class from the UA (the part common to all rangers, without subclass features) with a subclass from XGtE, rather than a subclass from the UA. By "compatible", I mean:

1. Is it correct that I would need to add Extra Attack to assure that the class is balanced with other classes?
2. Are there other differences with a similarly high impact that I would need to consider?

The reason I suspect they might not be compatible (at least not as written) is the fact that Extra Attack got relegated to the subclasses (except for the Beast Master, which now lacks it). I further assume that the XGtE subclasses were created with the original PHB ranger in mind, which means they would suddenly be seriously downgraded because they lost the Extra Attack feature.

Answer 1

They are not compatible

The Player's Handbook/Basic Rules version of the ranger gets a Ranger Archetype at level 3, while the Unearthed Arcana version of the ranger gets a different class feature called Ranger Conclave. The conclaves that go along with that feature are detailed in Unearthed Arcana: The Ranger, Revised.

Xanathar's Guide to Everything adds new archetypes for the ranger, not new conclaves (page 41):

At 3rd level, a ranger gains the Ranger Archetype feature. The following options are available to a ranger, in addition to those offered in the Player’s Handbook: the Gloom Stalker, the Horizon Walker, and the Monster Slayer.

It is a different class feature for an altogether different class, and they are not compatible.

If you wanted to use one of the archetypes from Xanathar's Guide for the UA ranger, you would first need to create (homebrew) new conclaves that mirror the XGtE archetypes, and worry about balance as part of that process.

Adding extra attack

I am not very experienced in homebrewing and balancing, but the Horizon Walker archetype from Xanathar's Guide to Everything was playtested in Unearthed Arcana: Ranger & Rogue, which includes this text block:

If you're playtesting the Unearthed Arcana ranger, you can use these subclasses with it if you make one addition: give each subclass the Extra Attack feature.

Extra Attack. Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.

The Monster Slayer archetype was playtested in Unearthed Arcana: A Trio of Subclasses, which contains a similar text block.

So if you are looking to balance these subclasses for use with the UA ranger, that may be a good place to start.

Answer 2

They are not very compatible.

Most of the officially added Ranger Conclaves have added powers that make up pretty well for the PHB ranger's deficits. Combining those with the UA Ranger's upgrades is too powerful. One example is how the UA Ranger has advantage on initiative, and the Gloomstalker conclave adds Wisdom to initiative. Having both of those would be too much.

What I do, is allow a player to use the UA Revised Ranger if they are going to pick the Hunter or Beast Master conclave. If they want a Ranger who operates in the dark, they can choose whether to use the UA Revised Ranger with the Deep Stalker conclave in the same article, OR use the PHB Ranger with the XGtE Gloomstalker conclave. If they want any of the other conclaves, they will use the PHB Ranger.