I'll grant you that ZA was basically a rehash, but Ragnaros, Nefarian and Zul'Gurub were all completely new boss encounters even if they were the same characters. Comparing the Raggy/Nef encounters from their MC/BWL to their FL/BWD selves is...crazy. With Raggy especially they're many magnitudes of complexity in difference.
You're completely ignoring Cho'gall, Sinestra, Al'Akir, Deathwing and the new TB bosses too.
I'd also note that ZG/ZA are now five-man instances, not raids as they were previously. We had a fair amount of new five-mans (including the HoT instances which - though gimmicky and not particularly challenging - were certainly new).
Evil Alpaca said:
Same with the new PvP. The new battlegrounds were just Arathi basin and Warsong Gulch with 10 and 15 player caps.