One of the things that I like about the original Guild Wars was that leveling was pretty much locked into the same speed from top to bottom, and it was almost incidental. The last new character I made and leveled hit Level 20 long before I’d finished any storylines, and I barely even noticed it until I realized that I could start getting her gear set up. I’m not saying it was ideal, but it was kind of nice that the game didn’t make half of the levels feel like a training film while making others feel like a slog.
Then again, games like World of Warcraft throw the early levels at you with almost no impact because the game is balanced around the current level band of the expansion; you’re not supposed to linger there. As it stands now, 1-90 takes only a bit longer than 90-100 by design. But that means that those first 90 levels may as well be removed, functionally – if you made the earlier levels slower, the higher levels faster, and tuned everything to have a smaller level curve, it would take the same amount of time with a smoother sense of progression.
I realize that this is something not everyone cares about. Some people like that you get all of your workhorse abilities early and lots of situational tools later; others prefer that early levels feel fast and trivial while later levels feel more impactful. What about you? What’s your ideal progression rate in an MMO?