Wanderer - Not sure if you've read some of my posts but you will notice I've been doing just that, giving enemies special skills. As a general rule, feel free to do the same. I. Want everyone to help populate with as much as possible.

Benefits of leveling up include the following:

- Ability to take on stronger enemies
- Use of better equipment 
- Unlock skills
- Upgrade skills
- Raise SP
- Unlock level specific quests and dialogue for secret bosses