5 points
*
Yeah D&D leveling is not linear at all.
- 1-3: Extremely fragile, casters can be one shot by most non-minions
- 4-7: Balanced, can handle most things with some prep
- 8-12: Basically unstoppable unless caught by surprise
- 13-20: Godlike
A single level can make a huge difference. Particularly when you hit thresholds for extra attacks or higher tier spells.