SMF is a talking point because people have been asking for it since it was removed, class rotational/ability changes during an alpha that nobody can test or really understand and that will continue to change are not going to be a big talking point. And yes people have complained about one simming higher but people complain about everything so who cares? For the vast majority of the time that SMF and TG were in the game together the dps was extremely close.
You talk about Cataclysm, but in Dragon Soul SMF was stronger than TG aside from TG having better weapons so still coming out on top in BIS gear. There was always one or the other slightly ahead, but it was always "slightly" ahead. In the most recent version of SMF (WOD) they were extremely close to the point where it was negilible. The only reason TG was ultimately better in HFC was because Archimonde didn't drop a 1h, but he did a 2h.
Blizzard has always tried to keep them close, but never made them identical, but they could make them identical using the D2 solution.