actually, now that you bring it up, let me point something interesting out.
2.3 - the 2.3 badge gear, which was more-or-less t5ish gear. iirc a large slot item was 50?? badges, and they introduced daily heroics for bonus badges. kara did not drop badges at this point.
2.4 - the 2.4 badge gear is t6ish ilvl. at some point in 2.4 kara started dropped 22 badges (which killed my nightly heroic runs). a large slot item was *150* badges - this was a LOT of work, or you waited 7 weeks and just ran kara. heroics remained quite capable of wiping groups. even by end bc groups I pugged in mech, for example, never routinely killed serpenthea and saved the attempt for last. the point is - mechanics did not forgive failure.
iirc badge-type gear became much, much faster to obtain in wotlk.
blizz released a new dungeon in 2.4 which was very hard at a t4-5 gear level. some groups wiped repeatedly.
blizzard also reduced bc heroic attunements from faction revered to faction honored at some point.
so by end-bc, a t5 group could go in heroic anything and have a much better chance of wiping than an ilvl 190-200 green/blue group going into heroic anything in 3.0.x lvl 80 (and no attunement required!).