I think in the expansions the leveling is improved a bit because Blizzard got better at design and added phasing. It’s still so easy that it’s rather boring, at least to me. First time through is the best because it’s all new, but after that it’s tedious.
A few days before Classic launched I resubbed so I decided to level a new character for the heck of it. I leveled to 31 and the only time I died was when I walked away from the PC without logging out. I was AFK longer than intended and what I thought was a safe spot wasn’t.