+1 to slower level progression. In particular, the jump from level 2 to 3 happens way too quickly. Level 3 should be attained sometime after the first grove battle - maybe after the first or second battle in the blighted village or swamp depending on the order done.
Level 4 could be reached after the grove battle (the full invasion one), or perhaps shortly before it if you explore the NW edges of the map before beginning the raid.
Then, it'd be appropriate to reach level 5 near the end of the Underdark.
If you did absolutely everything, you could reach level 5 at the beginning of the Underdark.
Not a fan of implementing "make X slashing attacks to unlock lacerate" types of mini powerups. Those'd be more appropriate for an mmo or hack n slash game.
