Replying to some great feedback I got privately:
Disappointingly empty skill tree and short skill lines.
Emptiness will be fixed with time. Short skill lines will not, as that’s part of the theme of the mastery - short, swift, and to the point.
Riftward doesn’t make sense… it’s something to stay close to, despite all these teleports and the apparent mobility theme of the mastery? I see potential in the skill as a thing to throw into enemy lines just for damage, much like storm totem, without giving bonuses for staying close to.
Riftward is a two part “problem”. The first part of it is that I kind of rushed the mastery as a whole (I made the whole thing in a day, sans skill icons) and Riftward took a lot of effort just to get to work, so when it finally did, I basically left it alone. The second “problem” is that it is an attempt to enable Riftstalker to be used with other less movement-oriented masteries (i.e., all of them). To this degree, I wanted it to function kind of like Wendigo Totem, in that it’s something you hover around. I still tried to make the radius large enough to give you some legroom if you wanted it, though. I think I’ll remove the cooldown from the skill so that if you’re moving around a lot you can still be guaranteed a Riftward wherever you wind up.
A potentially interesting idea: Tether could tether between Riftwards, like Aether Wisps
I don’t really know how viable this is; I only just figured out how Wisps do that a short while ago and Crate’s (limited) documentation on the matter doesn’t make it clear how to use it oneself. I would like to, though.
Teleports should have longer buildup animation.
I’d really, really like to…but I’m not sure I can. I tried to use some casting animations during development, but they seemed to screw with the actual teleport itself and leave you in place.
…I’m assuming you’re referring to player model animations and not PFX; PFX should be doable.
Tether and Void Syphon buffs should use different icons for clarity. Right now they both use the same.
Yes. 
Something-something made-in-a-day.
Warp feels punishing and terrible to use due to the insane energy cost, yet it does not feel worth enough to invest into to lower the energy cost. Maybe if it gave a nice bonus or anything other than being just a warp.
Warp is being removed and replaced with something else. It just feels too clunky to use the way I had intended, and is otherwise merely a means to break quest progression.
Of the Planes needs different/harsh penalty. To stay with the theme, maybe something like a debuf on casting, “Rift Sickness”. Could lower player speed or defenses.
Certainly won’t lower speed, as that goes against the whole mastery. A DA or Armor penalty is viable.
Void Siphon, the buff, should not use the heal sound effect since it does not heal.
Uhm…I’d have to check in-game, but there’s no SFX attached to any of the Riftward stuff.
Why is there % pierce damage on Korvoranian Tactics when there’s no source of pierce damage anywhere in the tree?
…Tether gives you flat Pierce Damage (and a lot of it). 
I can add some Pierce here and there, but this is, again, largely a means to make Riftstalker fit in with more masteries.
On the same note, there’s a complete lack of different damage types. It’s all just Aether and Chaos.
I may toss in a little bit of Vitality, Fire, or Lightning here and there, but Aether and Chaos (and Pierce) will be the focus of the overall mastery.
There’s also no “main” skill line that covers most of the mastery bar of a spammable skill that is defining for the class. Everything seems more or less incoherently puzzled together.
Swap has the potential to become a defining skill line to build around, but even so the mastery is lacking a spammable.
(To elaborate, in Soldier you have Cadence and Blade Arc, In Nightblade you have the dual wield line and Phantasmal Blades, in Demo you have Fire Strike, in Occultist you have DEE, in Arcanist you have PRM and in Shaman you have Savagery and Primal Strike)
Swap is intended to serve this purpose, somewhat, albeit with a slight cooldown. Otherwise, yes. And I don’t intend there to be. Riftstalker is intended to be purely a utility-esque caster that happens to have some spells that deal damage.
There’s no penalty for “All As One”, despite it being a transmuter.
The penalty is putting a skill point in it. There’s no penalty for Manifestation, Searing Strike/Might, Might of the Bear, or Corrupted Storm, (all vanilla transmuters) either.
Fleshwarped does not fit the theme AT ALL. Retaliation makes much more sense on tanks. Especially in these ridiculous amonts.
Again, trying to enable usage with other masteries. Every Zenith mastery has some form of Retaliation in it.
