For starters, better Revenant designs for those two.

Kabal's should resemble those masked guards you encountered in MKM's Prison of souls, those that wielded these high-tech guns.

Variant ideas for Kabal:

Hooksword: He should have them in all his variants, but this variant would add extra specials and combos involving them.

Speedster: Puts more of an emphasis on speed-based gameplay.

Gadget: Like those rotating blades, and that magnetic MKD special where he and his opponent knocked each other out.


Stryker

Special for two variations: A shield, that allows him to run through projectiles and ram the opponent.

Variants

SWAT: Mostly gun-based gameplay, with his grenades plus tactical smoke ones.

Riot cop: His most familiar variation, gameplay-wise. Adds more baton-based combos and specials, as well as taser ones, and pepper spray as a stun attack.

Hell's Enforcer: a Revenant variant where Stryker is equipped with some of those cool weapons from MKM like the staff gun and the plasma cannon. Can also set up those force fields from MKM's Hell stages that the opponent cannot jump over (teleportation is another story) but that can even hurt Stryker himself.

Finally, for that variant an horse should replace the shield. The story mode scene where he rode that horse was awesome, and I'd like it to factor in his gameplay in some capacity.