This week I found a few very amusing bugs in the code in WOW. Both relate to Divine Storm (DS), a spell which caused much controversy during WotLK, in particular because of the glyph. DS heals for 25% of the damage it causes and the glyph increased that to 40%. My guildies and the other ret paladins on EJ had many fights about whether or not that glyph was worth using over a really weak dps glyph. This discussion seemed like it had been buried forever when 4.03 came out and the glyph of DS was removed and DS was changed from a core part of the ret rotation to a bad AOE spell that wasn't even worth speccing into most likely.
But not so fast! Tier 10 had the benefit that it reset the cooldown on DS (proc on autoattack) back in wrath but this benefit was clearly not going to work when DS was fundamentally changed and removed from the rotation. The T10 benefit was changed to provide 5% more damage instead but they didn't bother removing the old benefit! This may have made sense at the time because DS was originally changed to be a finisher and to not have a cooldown at all but shortly after that they changed DS again to its current form: A replacement for Crusader Strike. It seems like the developers didn't bother to remove the old DS effect because it would not affect the new DS but they made that decision and then never revisited it after iterating more on DS.
This is compounded with the fact that the old glyph of DS was removed and replaced with the glyph of Templar's Verdict. (TV) They didn't remove the old glyph though, but rather just changed it to have the new effect but again forgot to remove the old. So now every ret paladin who is properly glyphed has DS healing for 40% of the damage it causes - we can't avoid using this bug to our benefit without compromising our basic abilities in other situations.
The reason all this matters is because DS got monstrously buffed in the last patch. It went from 80% of weapon damage to 100% of weapon damage + 42% more magical damage. It turns out that a 77% boost in effectiveness changes DS from a joke to a powerhouse. In a raid situation DS will hit for 10k per target and heal for 2700 per target under normal buff conditions. There aren't a lot of AOE situations I get to be part of but whenever I do get to hit 10 guys with DS I have a instant cast spell that does 100k and heals for 27k. That spell also has a 3.74 sec cooldown that is very regularly reset by autoattacking and drops to 3 seconds under heroism. This is *not* a reasonable situation. On heroic Halfus I was able to put out as much healing as the healers did while the whelps were up (which is the critical time) and do absolutely devastating dps. The nutty thing is when a fight happens to work such that all cooldowns including heroism are popped at once. This drops the effective cooldown of DS to about 2.5 sec and because the healing effect from it double dips with my AW I can easily expect to be healing for ~50k on each cast and doing 150k damage. I don't think that a dpser delivering 60k dps and 20k healing/sec with just *one* of their abilities during a AOE burn phase is at all a reasonable thing. Whether or not Blizzard is going to fix these bugs is unclear since they are really pretty rarely used but their power when they are called up is just over the top.