It just seems much less niche than it actually is, because there's very little point theorycrafting on anything but full BIS, because below that you're having to take so many different gear combos into consideration. But even at the full BIS level, we're talking maybe a few thousand dps difference between "optimal" reforging and proper talent choices, and suboptimal reforging/talents.
In real terms, most of the differences fall within the realm of rng. You're simply never going to have circumstances you can replicate during actual raids. No one's latency will be exactly the same, no one's procs will be exactly the same, no one's reaction time will be exactly the same, etc, etc, etc ... and even if you could guarantee all those variables, how many times do you even kill a given boss in a given tier ? Maybe 30 times if you start early and stay late ?
Of course folks who know what they're doing and are good at math and all that will be able to eke out more than most, but, yeah ... you see different perspectives because nearly every possible build is viable and several have strong niches. I'd say just give it a couple weeks after a given patch and you'll see the conversation distill down to a couple/few builds that work for the various situations you'll find in a given tier (I think we might be another week of gearing and mathing before the dust settles on this tier)
Unless by too much bullshit you mean from the developers radically changing Warlocks so often through MoP. Yeah ... hope that roller coaster is over with MoP, but ... guess we'll see.