If we follow the conventions of the Heroes and Nova Classes, each job would get one attacking skill and two buffs with plenty of passives. However, those passive skills are all boring and are probably very predictable (e.g. Shadowers will probably get boosts to Carnival Edge, Boomerang Step and Assassinate while I/Ls would get buffs to Glacial Chain, Chain Lightning and, knowing Nexon, Blizzard too).
Anyway, these are some skills I think would be pretty interesting:
You character generates a sword or hammer (like how Intrepid Slash does), runs and jumps into the center of the map and slashes, cutting the entirety of the map with prismatic elemental damage (i.e. Damage of all seven elements). Any monster hit by this skill loses any elemental resistances or immunities they may have and gains a weakness to all of them for 15 seconds.
For 120 Seconds, you can imbue your weapon with up to four different elemental charges. Cooldown of 240 Seconds.
Captain of the Guard:
For 120 seconds, all your party members (including you) take only 80% of damage from monsters while you take the other 20%. The damage you take is subject to all the damage reducing skills you may have. If and when your HP reaches zero while this buff is active, your entire party gains weaker versions of whatever elemental charges you had when you died. Cooldown of 300 Seconds. Of you had more than two every gets Lightning and a random one.
Your character generates a massive star, a la Avenger and hurls it forward. The projectile lasts for 10 seconds and can be guided by your arrow keys. It lasts for thirty seconds, at the end of which it explodes and deals fire element damage, which then creates a Purge Zone if you do not already have one active. You can explode it before the 10 seconds by hitting the Attack key. Cooldown of 20 seconds.
Your character impales stars in itself to reduce its maximum HP to 1. You are in Dark Sight mode and gain 100% Damage and 70% Status Resistance for the duration of the buff, which is thirty seconds. This skill tests your Luck and Avoid and your ability to bring a Bishop or Shadower. However, this is with the assumption one of your other Hyper skills boosts the dodge rate of Shadow Shifter. Cooldown of 90 seconds.
Your character throws up a web of charms not unlike Frailty Curse. Within the confines of this area, your party gains 100% Ignore Defense and ignores 15% Damage from monsters. It periodically restores HP and MP and lasts for however long Purge Zone does.
Named after the Mechanic Instructor, Checky appears and modifies your robot so that it can reach it's full potential. For 30 Seconds, your mount transforms into a futuristic looking tank. Pressing Jump + Up Key will activate rocket booster, while pressing Jump + Jump will activate hover mode, where your mount can fly. Your attack Key will shoot rapid fire blasts like that other mech skill whose name I forgot. Cooldown of 90 seconds.
United We Stand:
Summons either Checky in an elaborate suit of armor (imagine the Power Suit Mount but bigger and with a bear motif with claws and pomegranate), Belle appears riding Black Jack, Brighton with a blood red aura. Each of them will be summoned at a 33% Chance. At a 1% Chance you will summon Claudine or Elex. The chances that they are summoned can be increased to 10% with another Resistance in your party, 15 with two, 20 with three and 25 with four. For thirty seconds they will aid you in battle. However, if one of the instructors is summoned in your party, another resistance cannot summon the same one.
Checky uses Punch Launcher, Siege Mode (though he doesn't actually transform) and Rocket Jump.
Brighton uses Finishing Blow and Twister Spin. His aura restores HP and MP and increases status resistance for characters near him. He can Teleport as well.
Belle uses Wild Arrow Blast, Swipe and Blind.
Claudine uses her own version of Assaulter and Demolition/Carnival Edge and that skill that Kaiser has with the grappling hook. She has a movement speed of 220.
Elex uses a version of Ground Smash/Shockwave, Double Upper and Barrage. His movement speed is the slowest of the lot but he is by far the strongest of the five.
They each do damage proportional to a fifth of the person who summoned them. Elex, however, does up to a third.
Pushes your machine to the limit by increasing your boss damage by 25% and your defense ignore by 100% and your Speed is increased to 200. However, you will constantly take 5% damage to your HP every four seconds. Lasts for 20 seconds with a cooldown of 90 seconds.
Next Up: Dark Knight, Marksman and Mage Classes