I'm sorry, can you clarify where you're getting this sentiment from exactly? True, Blizzard occaisionally experiments with certain mechanics at the cost of player's sanity, but how else are they supposed to get reliable real world data? (that's a trick question, the answer is they can't, so please no "sim's" straw men). They will not allow a talent to completely overwrite one play style if their entire point is to provide two. Now, on a single target fight might this be the "best" choice by a slim margin? Possibly. But that's min/maxing tripe and if people really feel the need to justify their toxic elitist behavior by arguing how an incremental, minisicule, theoretical increase like that (and boy will they ever), then they can, but ultimately people will choose to play with the way they are comfortable proficient with. Also consider that at present the current, "traditional" play style of shadow priests is ridiculously inferior on fights were there are not 3+ extra targets for multi-dotting.
Haven't done a whole lot of reasoning on this one, have you? Two buttons? Try 5 - which is the magic number Blizzard has been aiming at since the end of WotLK. Mind Spike > Mind Blast > Devouring Plague > Shadow Word: Insanity > Shadow Word: Death (with the glyph, yes, that's right, Divine Clarity would actually make that glyph useful). Remember, it buffs all the non-damage over time spells, and SW
is one of them. As it stands you'd have to spend the Shadow Orbs on Devouring Plague still, which means you'd wind up taking Solace/Insanity - FDCL is worthless as you won't be casting VT, and Mindbender isn't so much a viable option when you're casting DP anyway, unless your goal is to just be recalcitrant. Granted Blizz may shake it up and make it actually optional, but we won't know until we get the beta and start doing some math. /shrug
Don't shout the sky is falling because Blizzard wants to give spriests an alternative playstyle (we've only got one damage spec after all), it could very well be the answer to spriests abyssmal competitiveness. That and PEWPEWPEW. Heh.
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DoTs have defined Afflication as a Spec too. And Warlocks have two other forms of inflicting top tier damage. I'd be far more affronted at the notion of an alternative to DoT's on shadow priests if we weren't the weakest damage dealer on any fight without 3+ adds and the 3rd weakest DoT damage dealing class (behind Warlock and Boomkin, respectively). And I'm talking about progressive end game people, not LFR - In order to be "good" at Shadow Priest you basically have to come out of the gate as a try hard, essentially like wearing weighted training gear. You get used to playing at such a disadvantage that you feel so good when you do well, when in reality all that extra effort should have you seated prominently at the #1 slot. It'd be less noticable if people were recruited and brought to raids based off their apptitude and ability, instead of how much potential damage they can/should be doing.