Level 1
Heavy Shoulder: Improved slow and cooldown reduction for Overpower.
Seasoned Marksman:
Quest: Every Minion killed near you grants 0.2 Attack Damage, and Takedowns grant 0.5 Attack Damage.
Reward: Upon gaining 40 bonus Attack Damage, you can also activate Seasoned Marksman to increase your Attack Speed by 40% for 3 seconds. 60 second cooldown.
Supreme Commander's Quest:
Quest: Hit 25 Heroes with Slam.
Quest: Participate in 4 Hero Takedowns.
Quest: Gather 15 Regeneration Globes.
Reward: Completing a Quest grants 15 Slam Damage. Completing all 3 Quests grants 20 Base Attack Damage.
Level 4
Soul of Thoradin: Battle Cry of the Arathi now preventing all incoming damage except of selected target.
Lion's Claw: Slam now causes enemy to bleed.
...
Otherwise kinda... Dull and nothing more to say about it.
Or just save the concept before publicking it :P