Q is impossibly good escape ability, E works as a secondary escape skill
Great CC with focus and E
Shuts down ranged attackers with hellburst
When Q and E are on cooldown you're a sitting duck
Doesn't have the CC potential of other builds
Foregoing counter lowers ability to disrupt creatures
Rushing smackdown helps when dealing with early creature summoning on most maps, giving Margrave the ability to both disrupt summoning on the point and get out easier when outnumbered.
Doom Strike gives Margrave great wound damage potential, in addition to general killing power, as his wound damage can't be blocked or deflected and his extreme tankiness prevents him from being easily bursted down.
Depending on the build of the enemy's team, it may be safer to change the build to get Pure Agression before Eternal Flame and Give Em Hell, or vice versa. (Picking up EF and Give Em' Hell 4th and 5th against a team with an Imani and T-MAT or getting Relentless and Pure Agression 4th and 5th against a team with Pakko and Xenobia, for example). Similarly, if the opposing team is always bunched together, get Demon's Reach earlier.