After max level, each additional level grants you a stat point to allocate toward 3 skill tree categories, with each tree granting exclusive perks.

• Endurance (Heavy weapons/ranged skill/defense specialization)
• Reflexes (light weapons/Melee/speed specialization)
• Elemental Attunement (Elemental damage/status effect/ultimate skill specialization)

Make the perks nifty, but not essential. No one will complain if there's no PVP. Plus, having a baseline carrot to grind will soak up some of the salt even if RNGesus is being unmerciful.