Nostalrius Begins - Quality wow vanilla realm (1.12)

Hey guys, i have a question about Imp Drain Soul tallent. My first reaction to seeing the tallent getting points in the "definitive warlock guide" was that is was kinda sucky.
But i missed the second paragraph.

In addition you mana may continue to regenerate while casting at 50% of normal.

After reading that it turned from beeing kinda bad tallent to super awesome but im not sure i have fully understood it yet, 50% out of out of combat regen? is that correct? Isnt that really powerful? Should warlocks stack spirit?

visceral89 wrote:After reading that it turned from beeing kinda bad tallent to super awesome

Yes, it is awesome.

visceral89 wrote:50% out of out of combat regen?

Yes, that is correct. 50% of your OOC MP5.

visceral89 wrote:Should warlocks stack spirit?

Short answer, no, warlocks shouldn't stack spirit per se. But don't overlook a piece of gear just because it has spirit on it. Spirit is not a typical warlock stat because of Demonic Embrace, but that does not mean that it is completely useless.