You do realize that there are people who enjoyed that specific playstyle, right? ISF Affliction was one of the most entertaining things ever. Sure Shadow Embrace was annoying and I'm glad they removed it, but saying that a dot class is better of without tab-dotting is just plain silly.
So you not only assume that most of us haven't played back then, but also state that no one enjoyed it more then MoP Affliction, because you didn't? Swell.
Furtheremore I doubt anyone has anything against Soul Swap, the spell was fine back when it had a cooldown and allowed you to swap targets instantly.
The annoying part about this subject is the fact that nowdays you press one button several times to put your dots up on a certain amount of targets. I play a dot class and I don't want to multidot, so instead of swaping specs so I won't have to I want blizzard to give me one button to rule them all.
That's not a good design, but exactly what you mentioned regarding nerfing Demonology - straight up dumbing something down to appeal the masses.
Look what they did to Demo in MoP. They turned a pretty boring cooldown based spec into something with depth. With Affliction they did the exact opposite.