Do you have the core rules?
I like your idea of a base ability that defines the classes. That's cool. What I'd advise is putting together lists of selectable abilities, like the talents in the core d20 modern rules (only, ones that don't suck). Most should only be able to be taken once, that way they can be extremely cool.
So Blitz could get a few trees: Close Combat, Fast Mover, Unbreakable, Champion, and Vid Star.
Close Combat talents emphasize melee combat (+2 melee damage, +1 to melee attacks, improved unarmed damage, +2dX on melee critical hits, improved critical, etc).
Fast Mover talents emphasize speed, using cover, and closing with the enemy (+10 ft speed, charge at angles, +20 ft charge speed, +2 attack / defense when charging, x2 damage when charging, etc).
Unbreakable talents emphasize durability and willpower (+1 DR per, energy resistance, evasion-like ability for Fortitude, evasion-like ability for Will, bonus hp equal to class level, +5 bonus on MDT saves, etc).
Champion talents would be more mystical, kind of like D&D paladin powers. (+X to saves, SR 5 + Class level + Charisma, +10 vs fear and +4 to allies, don't auto-fail on natural 1, etc).
Vid Star talents are for those Blitz characters that are celebrities, granting both social and action benefits. (+X to interaction checks, +X to stuff done in front of an audience, etc).
Then do something similar for the Ranger: Sniper Shot, Close Quarters Shooting, Quick Draw Artist, Exhibition Shooter, Zen Shooter.
Sniper Shot is all about long range, aimed fire.
Close Quarters Shooting is about gunfire in people's faces. The high end would be some kind of gun-fu.
Quick Draw Artist is a reactive shooter, good for duels (think Old West) or reacting when surprised. Emphasize drawing, firing, and holstering for each shot.
Exhibition Shooter is the Ranger version of Vid Star; a performance shootists, best when "on stage", with a few benefits from his reputation.
Zen Shooter is somewhat mystical, pulling some inspiration (if not mechanics) off the Arcane Archer prestige class.
Good luck.