The flip side of this advantage is the need to concentrate multiple roles worth of gear on the same person and the highly limited usefulness of doing so. In all my years of raiding, I had exactly one opportunity to flip to a secondary spec to handle a unique problem and that was on Yogg-0 10man. We only needed one Tank and I had just enough viable caster gear to make going Balance worth while, especially since the fight favored DoTs and Casters so much.
Outside of my solitary personal example, the only time I saw people swapping specs was Healers going DPS or vice versa for specific fights, and typically it was the same person flip-flopping, and typically we only cut down on Healers on farmed bosses with no real punishment.
In TBC we’d see DPS swapping between Tank and DPS as needed, given the wide disparities between Tank needs in 25m bosses, but honestly that only impacts a remote few encounters that aren’t even the crux of the matter anyway.
I get that dual spec adds better fluidity in adapting a perfect comp to the raid, but that comes with a lot more preparation and overhead and frankly any guild willing to plan out that far is already the kind of crazy zealous guild that most of us don’t run with.
The positive side of all of this is the fact that casual guilds who are more likely to have random no-shows, people AFK mid raid, etc, now can have people more flexibly meet the needs of the raid on the fly. Time is a limited resource even for these folks and they don’t want to be in Karazhan or SSC forever. Being able to swap then and there to fill in for a DC’d Tank or an AFK Healer is exceptionally helpful.
I just see far more good than bad and even if Dual Spec were to become inextricably linked with the fastest of the fast speed runs, I’d be OK with that. That kind of meta chasing trickles down and people who never thought to try actively using alternative specs like that suddenly have a reason to chase down caster gear on their otherwise Feral Druid.
This is a case where I think Dual Spec only adds options without actually taking anything away, so aside from social pressure to maintain two “meta” specs to swap between as needed (as opposed to just one), this helps everyone out and makes alternative playstyles a bit more attractive to play around with. And I get the irony of dropping 5k gold to make this feel accessible when a short flight and 50g (at worst) can get you the same thing… people just like unlocking things.
I’d pay 5k gold if I got an Endless Flask of Fortification that I could chug once every 2 hours just so I never have to go to the damned AH again. I get it is just laziness and convenience, but I’d be willing to pay out the nose for that kind of laziness and convenience the same way I did for epic flying.