Balance issues.

The Slayer gains way too much at level 3 and 7. Drop one of the level 3 class abilities and one of the level 7 ones as well. A Sneak Attack, acces to the secrets and talents. Not to mention the talents and secrets are pretty strong for gaining them every 3 levels and being able to choose. Enemy of Nature is also way too strong. Being able to have a bonus crit which is an a Class ability in itself for the Champion, pick a quarry who tracks sper easily and has advantage on attacks on. Seems a little broken but a great concept.

Also, your level 10 ability comes before both level 7 ones.

Happy Gaming, T.G.