This functions really, really oddly in my testing to the point of near-annoyance, and it doesn't make much logical sense either. Alright, we know how this power works. When you tap, you target an enemy and teleport to them to shove a ceramic dagger up their ass via heavy attack. When you hold, you can place what I like to call a "blink marker" that you teleport to at the end of the hold. When you tap the button without any target you will not teleport at all, you'll just get the "invalid target" prompt, which makes it rather awkward to use.
Now, the simple "solution" to this is to invert tap/hold inputs for Kullervo in the options, but this is precisely where my problems begin. When you tap to teleport it does work well, absolutely 0 issues, but I've noticed something: if you tap to teleport and your destination is near an enemy, you will do the heavy attack. The same happens with hold to teleport, where if your marker is near an enemy it will force you into the heavy attack.
My problem is as such: why not allow us to teleport via both taps and holds and use the function I was just talking about to heavy attack as required? As it is we have to choose whether we want sporadic or precise teleports, when we should have access to both. The existence of a dedicated "tap/hold exclusively to 'nothin personnel kid' someone" is meaningless when, again, we can just look at an enemy, press or hold the button, and do the same; more tactical flexibility at no cost.