My rogueling is only level 15, but at least for questing, I’d say yeah, it’s more difficult.
But it’s not the kind of difficult that would make me a better player. I already am aware of the talents I need to take, and to keep SnD up, to keep an eye for patrols, etc. The only aspects of my gameplay I can actively modify to improve my chances would be to
-Get a better understanding of energy chunking (as it is dramatically different to Live, and I didn’t get into rogues until Cata)
-Just be way more circumspect, ie, careful to the point of not engaging targets.
I’d say the last bit of content that was difficult and that pushed me to really improve my gameplay was the Mage Tower (for some specs anyway)
So far, Classic has me wishing for better RNG on green drops and more groups of people I can join to complete quests.