The TBC gear also has some superior itemisation like no strength on rogue gear that gives it an advantage.
IIRC the aldor rep epic sword was 81 dps and was the best thing until spiteblade from kara which was 87?. KT sword has 73 dps. That is the sort of gradient there is so likely people will be raiding kara in naxx gear.
I simply cannot relate to this idea at all. If you do not enjoy getting the gear then why play at all. What are you going to do when you get your gear from naxx? Probably exactly what you were doing before you got it...