I really, really hope it has a "brutal finishers" mechanic.
For example, an Adept could raise a wounded enemy into the air and crush them with a collapsing biotic field, blow them up with an expanding field.
An Engie could flash-freeze an enemy and smash them, go full Palpatine and overload their nervous system, immolate them.
A Soldier would have more power-focused finishers, like suplexes, head stomps, gun-based kills (plant sniper rifle upwards, press an enemy's head to the barrel and fire, point-blank SMG clip to the chest, pistol whip an enemy to their knees and headshot for example).
Infiltrator would be more precision-based, like neck snaps, knife finishers.
Vanguards would biotic charge and impale foes with their hands.
Edit: Forgot Sentinels, the idea would be that they focus on their Omni-blades. Impale and decapitation, cross-slashes, leg sweep and impale.
These are just examples I could think of, I really liked the finishers in DA and was hoping they'd bring them to ME, considering we already have the grab-kills and Husk/Abomination head stomps.