BC: Warlocks hit lifetap to get mana back by sacrificing health. Some (bad) warlocks hit LOTS of lifetaps all at once scaring the healers. Warlocks cackle maniacally.
Wrath Development(late 2008): Blizz consolidates gear so Warlocks are sharing gear with priests and mages. This means that everyone will be getting Spirit gear now. Warlocks have NO use for spirit.
Oct 2008: On the Beta, Blizz say “Lifetap will now scale with spirit instead of Spellpower” (“I got spirit, yes I do“)(“scales with” meaning the tap will take away more health and award an equal amount of mana. The calculation is 710 + (3 * SPI))
Feb 2009: Blizz introduces the “Glyph of Life Tap”(“It’s the end of the world as we know it“)(you gain 20% of your spirit as spell power for xx sec)
Warlocks start tapping throughout the fight to keep the buff up. Spirit is finally worth something 2 SPI = 1 SP in calculations.
Dec 2009: Blizz updates the Felhound so that it does decent damage and regnerates more mana than it’s using even when all-out attacking. (“My pet’s better than your pet“)
Affliction warlocks switch to using the Felhound.
January 2010: Blizz introduces T10 armor. Warlock T10 has very little spirit on it.
Blizz also updates Glyph of Life Tap so that it sometimes procs when Dark Pact is used.
Warlocks begin specing out of Improved Life Tap and into Dark Pact (Life Tap scales with spirit which we have less of.. and Dark Pact can also trigger the Glyph’s bonus).
Feb 2010: PTR note for patch 3.3.4 says “Life Tap: This spell no longer scales with spirit, and instead scales with spell power.”
Since we’re in Cataclysm Development.. I wonder if they’ve decided to remove Spirit from a Warlock’s “must have” list for stats. Even further.. I wonder if they’re moving spirit off of gear.. We -still- have to share gear with Priests and Mages.. I wonder if that gear will be spirit-less.
In fact, now that I think of it.. I think they said they wanted to make Spirit be something that only healers cared about.. so maybe they’re moving that into the talent trees. That’d be spiff.
In that case, I wonder when the Glyph of Life Tap will be changed.