This to me sums up the core issues and puts it sensibly.
I personally think it’s not in the spirit of TBC due to it being something the original devs even commented about and gave reasons for not including. That is much of why I oppose it for tbc. But it’s actually not a massive issue for me. If it got added I’d still probably play.
I think adding it will further erode the reasons for grouping up in the open world. It will also cause various classes to be stacked in raids more due to eroding the niches some specs bring.
But there are bigger problems with the game right now such as server imbalance and low pop servers.
The disingenuous “debating” on it is a big issue for me. There are some that are campaigning for it like a national election, using all the same shady arguments. That’s what keeps drawing me into the discussion.
Edit: I don’t believe that people aren’t playing the game because they can’t Dual Spec though.