The gothic UA doesn't say anything about can't be healed with magic. That is cool if you want to houserule it that way, but it isn't RAW (or as RAW as UA's get). Technically it doesn't even change your type to undead, so hold person works on you, you can walk on hallowed ground, etc.
The biggest thing you need to realize is that the Revenant player is a very story based option and is not really mechanically balanced. The combination of Regen 1 and the fact it is not automatically disabled when you are knocked unconscious means that you are almost impossible to put down as if you do not kill them instantly, they will regain 1 hp at the start of their turn, waking them up. Revenants really are relentless.
Furthermore, they know where your target of vengeance is supernaturally.
Finally, on success the hero dies. The Revenant is by definition a tragic hero, as at the end of his quest he dies forever. This is the tradeoff for being granted all of these powerful gifts rather than being resurrected in a normal manner.
In Short: Know you are giving the player a very powerful ability to be literally unkillable in the sense that even if killed, they will come back. And the player needs to know this character now has an expiration date.
One of my PCs became a revenant after he was killed during the Death House adventure (another slain PC was temporarily possessed by Rose, but I digress). I did not use the actual UA rules for revenants, and instead made it almost exclusively role play. He had sunken eyes and pale skin, and the Night Mother gave him 30 days to complete his quest before he was dead for real. I allowed him to resurrect if he died, but every death would eat 1d6 days off of his clock.
It ended up being a non-issue as, when the party was "gifted" with a Deck of Many Things by Strahd, that PC drew the void and his revenant soul was sucked into the crystal heart in Strahd's castle.