The more than doubling between levels is ridiculous. It’s actually anti-gamifying because obtaining the next level becomes so burdensome that people will simply stop trying.
So please:
- Get a hold of the World of Warcraft XP level cutoffs.
- Decide on how many hours a user should have to spend to reach level 90
- Using that number and the average observed points per learning hour, scale the XP levels appropriately.
You do NOT have to design 90 separate and different Ziggy icons for this. Just like add some flames or change the color or size or something: it simply does not matter. Seeing yourself progress closer to the next level and the dopamine hit from obtaining that level is what matters.
The leveling idea isn’t a terrible idea (you had a badge system before is seems?), it’s just that your implementation is awful.