Harder? I dunno. I think they just required a bit more patience and concentration... If you use ToC tactics and current 3.3 5man heroic mentality of "round 'em up and AoE'em down", then...ya.. MUCH harder...
I think they're doing the players a disservice in reducing the need for players to use more of their skill palettes. Rather than spam a few buttons and see BIG numbers (isn't that why they added Lava Burst for Shaman? to remove the lightning bolt machine gun with Lightning Overload and the Lightning Capacitor procing like mad?).
Seems to me that the skill players aren't so much "harkening back to the halcyon days of yore when all was well, the game was perfect, noobs were easy to spot, ninjas, baddies and dbags were marked with green hunter's marks over there heads so all could see and ridicule them while keeping them away from their loots and their raids... etc", but rather that encounters required the use of more than hyper-specified roles. Well, BC did. I think vanilla was probably worse than LK in that regard. BC seemed to have some really nice encounters which required teamwork.
Anyhoo, today it's straight tank, dps, heals. Unless a heal or dps is to ONLY dispel or interrupt... Seems the organic nature of being well-rounded and complete, skilled with a full knowledge of one's class doesn't really mean much these days especially when it comes to dps. Skilled tanks/heals always seem to be able to distinguish themselves (cuz there's always something silly a dps is doing...).
I mean, I recently rerolled a rogue from Ele shaman after the Ele debacle... practiced sapping and various other roguey skills I'd known other rogues to use from vanilla and BC. I mentioned this to LK rogues now and to a person, every last one asked me... WHY???
And that is where the design failure occurs. I dunno if that can be changed before Cata due to the need to change stats, boss dmg, heals, dps, etc. A LOT has to change...
Still... I dunno that it's so much wanting a more complicated rotation cuz being mut and sweating keeping rupture up isn't much fun... but knowing I have all these tools in my bag that I never get to use... that rogues used to HAVE to use... (and that's similar to other classes as well) well... seems the experience has narrowed, diminished, become overly specialized. Not that I want rogues to heal or anything, hehehe, but simply having variations on the tank & spank theme seems to have really narrowed the experience of each role.