Doubly funny, TBC had some of the worst PVE balance problems ever. Tier 5, at release, was absolutely broken. A good chunk of tier 5 bosses weren't killed in their launch versions (Al'ar, Morogrim, Solarian, Kael'Thas, and possibly a few others in SSC). Even Karazhan, probably the best raid in WoW history, had several balancing problems. Nightbane, alone, went through somewhere around 3-5 revisions post-launch (let's bring as many paladins as we can so we can BoP his skeleton spawn ability!) and Shade of Aran was the fight where you swapped someone out for a second warlock. Oh, and who can forget the Sunwell debacle? Let's bring as many shamans as we can so we can rotate them into the strongest DPS party for heroisms... and let's not bring any mages.
Yeah, TBC sure was a shining example of PvE balance and consistency.