This has to be the worst out of touch take I have ever seens. All your arguments are completely invalidated by the simple fact that respec exists.
It really looks like you never played vanilla wow. We had free respecs during raids using guild funds… Unique? Mate we were all practically running the same builds. Renown? You do know that players respeced for other stuff and where still known for their tanking/heal/button smashing regardless of their current build right?
Seriously, go out and touch some grass mate. The only thing that dual spec does is simplify the respec and it’s only limited to 2 builds…
I’m playing a warrior. Not a tank, or dps, a warrior, I can tank and/or dps. A mage plays a mage, he’s not a frost or a fire mage, etc…