Broxigar by chubra

Level 1

Hack and Slash (Q): Quest (!): Hit 2 or more enemy heroes at a time with a single Cleave. Reward: After hitting 20 enemy heroes, add 1 charge to Cleave.

Double Edged Axe (Q): Every 4th basic attack unleashes a free, untalented Cleave that deals 70% damage.

Combat Momentum (D): Whenever Broxigar absorbs damage with Combat Resilience he gains 25% movement speed for 3 seconds.

Level 4

Battle Endurance (W): Increase the duration of Overpower damage bonus by 1 second. If Overpower lands a killing blow on an enemy hero, Broxigar immediately gains Combat Resilience.

Epicenter (E): If only one enemy is affected by Slam, increase stun duration from 1 to 2.5 seconds.

Lust for Battle (E): If Broxigar hits at least 2 targets with Slam, reduce Slams cooldown to 6 seconds.

Level 7

Giant Destroyer (W): Overpower deals additional 20% of targets maximal health as damage. Only affects targets above 80% health. Doesn't stack with Combat Resilience buff.

Blackrock Banner: Activate: Place a war banner with 500 health at a targeted location. Lasts for 10 seconds. All ally heroes gain 20% Attack and Move Speed. The banner takes 80% reduced damage from AoE abilities. Cooldown: 40 seconds.

Mage Slayer (D): Quest (!): Absorb damage with Combat Resilience 25 times. Reward: Increase spell damage reduction of Combat Resilience by 10%. Quest (!): Absorb damage with Combat Resilience 35 times. Reward: Permanently gain 10% spell armor.

Level 10

Axe of Cenarius: Passive: Cenarius' axe is sharper than any steel, ignoring 20 armor on every attack.
50 Mana. Cooldown: 20 seconds. Activate to empower the axe. Next target hit will be rooted for 2 seconds.

Battle Cry:
100 Mana. Cooldown: 70 seconds. Broxigar lets loose a powerful war shout, petrifying his foes. Enemy targets affected by the shout are Feared for 1.5 seconds and have their Attack Damage, Spell Damage and Attack Speed reduced by 30% for 5.5 seconds.

Level 13

The Red Axe (Q): After using Cleave Broxigar's next attack deals 70 (+4% per level) damage over 3 seconds. Stacks 3 times.

Blood Gorged: Activate: Heal for 300 (+20 per level) health over 3 seconds, remove all crowd control effects and become Unstoppable for the duration. Cooldown: 80 seconds.

To My Side!: Activate: Broxigar charges to a targeted ally hero, granting them a stack of Combat Resilience, while refreshing his own stack. Cooldown: 30 seconds.

Level 16

Might of Saurfang (W): Using Overpower on Minions and Mercenaries instantly kills them. Enemy heroes hit are stunned for 0.5 seconds.

Earthshaker (E): Slam deals 200% more damage to structures and 100% more damage to Minions and Mercenaries.

Jump Off (E): Slam can be cast a second time for free for 3 seconds after the first one.

Massacre (Q): Reduce cooldown of Cleave charges to 6 seconds.

Level 20

Gift of Cenarius: Axe of Cenarius active now roots all targets in a small area around Broxigar for 2.5 seconds.

To Victory!: Battle Cry also improves Attack and Spell damage of all affected ally heroes by 25% for 4.5 seconds.

Battlemaster (D): Combat Resilience gains a 2nd stack and reduces cooldown of both stacks to 8 seconds. Both stacks share the same cooldown.

I imagine Brox to be similar to what he is in the lore - overall badass. I find that his basic kit is some sort of a standard warrior/fighter kit. With that in mind, Broxigar's design is that of a DUALIST especially with right talents, although Brox can serve as a powerful TEAMFIGHTER as well, again depending on talents. Although most warrior kits can be quite simple, Overpower and Combat Resilience combo mechanic can contribute to some interesting gameplay. Combat Resilience on it's own can lead to some interesting play: running away from Kael'thas' Pyroblast and waiting for traits cooldown to finish can be nerve wrecking for both players.
As for numbers, I believe that they are balanced: Brox was never imagined to be able to burst (he wouldn't make much of a dualist), but he is able to steadily overcome his opponents in battle.
Now can Broxigar tank? Not really. He can soak a lot of damage and get away with it with his trait which was the general idea, but this requires timing and some luck. A smart player can bait his trait with a basic attack or a poke-low-damage spell. A smart Broxigar player can make the most of Combat Resilience by using it to close the gap with Slam and lock on his enemy.
As for heroics: both are good from 1v1 and smaller skirmishes all the way to full team battles w/ or w/o objectives (Garden of Terror, Dragon Knight, Spider Queens, ect.). Axe of Cenarius may be a more selfish choice (because of -20 armor on hit) but it's root effect can benefit the team as well, especially with Gift of Cenarius. Battle Cry on the other hand is an obvious power-up for Brox's team both w/ and w/o To Victory!, but it too can be more "selfish" and used for more of a "dualist Brox build".
I wanted the talents to grant utility to Broxigar, not to define him. Whatever you pick you can still be a strong bruiser with some preferences, rather than disabilities.

09/18/17 (18.09.2017)
Published.

09/22/17 (22.09.2017)
Combat Resilience: Cooldown decreased from 12 to 10 seconds.
Cleave: Charge cooldown increased from 5 to 10 seconds.
Cleave: Mana cost reduced from 50 to 40.
Level 13 talent Blood Gorged: Healing now takes 3 seconds to completely heal (down from 4).
Level 13 talent Blood Gorged: Cooldown lowered from 90 to 80 seconds.
Level 20 talent Battlemaster: Cooldown of stacks reduced to 8 seconds (down from 10).
Additional talent added to Level 16:Massacre.

09/27/17 (27.09.2017)
Level 13 talent Blood Gorged: Added bonus effect: Broxigar now removes all crowd control effects and becomes Unstoppable for the duration of Blood Gorged.
Level 13 talent To My Side!: Added bonus effect: Now also refreshes Broxigar's stack.
Level 13 talent To My Side!: Cooldown lowered from 40 to 30 seconds.

10/07/17 (07.10.2017)
Level 1 talent Double Edged Axe: Damage increased from 60% to 70%.
Level 7 talent Giant Destroyer: Damage increased from 5% to 10%.

10/18/17 (18.10.2017)
Slam: Base damage reduced from 200 to 170. Damage per level increased from +20 to +23 per level.
Level 7 talent Giant Destroyer: Now affects targets at 80% or above (up from 70%).
Level 13 talent Blood Gorged: Healing per level reduced to +20 per level (down from 28).

10/26/17 (26.10.2017)
Battle Cry: Added bonus effect: Now also reduces Spell Damage of affected enemy Heroes.
Battle Cry: Damage and Attack Speed reduction duration reduced to 5.5 seconds (down from 6.5).
Level 1 talent Combat Momentum: Now increases move speed to 3 seconds (up from 2).

3/17/18 (17.03.2018)
Removed flat damage increase per level and added +4% increase instead to all basic abilities and some talents.
Minor text changes.
Level 7 talent Giant Destroyer: Increased bonus damage from 10% to 20% of maximum HP.

5/31/18 (31.05.2018)
Slam: Mana cost reduced to 60 (from 80).
Added color to ability text (for pure aesthetics!).
Added Basic Stats for Broxigar.

7/22/18 (22.07.2018)
Axe of Cenarius: Mana cost reduced to 50 from 70 Mana.
Level 1 talent Combat Momentum: Move speed bonus decreased to 25% from 40%.
Level 7 talent Mage Slayer: Damage absorption requirements lowered from 30 to 25 and from 40 to 35 respectively.