I never thought of 2E as old school, probably because it was the edition I began playing the game with. It also just feels very different in tone, though I suppose the mechanics are similar to 1E.
1E settings and adventures feel very minimalist, in terms of why the PCs were there, what impact their adventures had, etc. 2E, by contrast, was the golden age of fluff in D&D, because it wove very strong narratives across everything; adventures, settings, even sourcebooks all helped create a very strong and cohesive feel for the various campaign settings (and the holistic meta-setting) of the game.
I liked that a lot, and was sad to lose that in 3E, though the much better mechanics helped me view it as a trade-off.