Removing the resource cost of Siphon & Tether makes sense, but nerfing the resources they return was wrong. By comparison, the Warden's Netch returns 4800 Magicka/Stamina over 27 seconds for FREE and has no other casting restriction. Corpse abilities have an additional casting restriction, have a much lower duration, and even worse - return a paltry amount of resources for the time invested in casting the skill. These corpse skills should last much longer (~20 seconds) and return a lot more resources while active. (
For balance, perhaps scale up the resource return the longer the Siphon/Tether holds to encourage "strategic corpse placement"?)
The current 12 second duration conflicts with other corpse usage and the resources returned, even with the initial resource cost removed, is still not significant enough to warrant use. A simple 20 second duration (with adjusted damage/healing values to compensate for the new duration) would address the Necromancer's sustain issues significantly and help make corpse usage a much more integral part of the rotation which is clearly what your patch notes are trying to achieve.
@ZOS_BrianWheeler
“Let your plans be dark and impenetrable as night, and when you move, fall like a thunderbolt.”