Hmm. I played on Adept, and used a bunch of skills (like, 10-12) with my first character. My leveling was pretty slow, and enemies gave me decent challenge up into the upper 40's.
It all depends on playstyle and how you level your skills. OP mentions that his Smithing is 60 already at lv26. I'm pretty sure mine wasn't nearly that high.... if I'd leveled it up that much, then, yeah - I'm pretty sure I would have leveled faster (since higher skill-ups are worth more leveling xp).
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on the larger topic.... no, I didn't really find leveling to be "too fast". Yes, it's quick at the beginning (low xp needed per level) so that you can start getting some perks & stat gains down, and define your playstyle a bit. But then it slows.
Also, I didn't use any of the "faster leveling" guardian stones.

(I hit around level 50 at...... 80, 90 hours?)