Endless Realms it is then!

I'm a bit partial to Mythics/Mechanics since I can see Flyers/Riders being more of a class than an overhead classification of the factions.

Main classes for Mechanics:
Gunslingers – Sleek dual pistol uses, focused on speed and light armour attributes; effective with dodges and short-ranged, fast paced attacking. Low defensive and low endurance.
Saber Soldiers - Large laser swords (not exactly Star Wars) usually between three to five feet long. Each laser saber is customizable in shape and power, the more power, the less speed a user has. The less power, the more speed they'll have. All around flexible and strong. Though when a user's health is in decline, so is their weapon as it's a digital feed reflecting their health.
Hyper - ???

Sub-classes: (Sub-classes are geared in concept to their respective side of the world, but there are many players who use this opportunity to cross-class and mix sci-fi with fantasy in their character, as they can be taken as a secondary to one's chosen "Main Class")
Technician - Can fix/upgrade/create weapons and armours.
Hyper Vigilant - Explosives and gear experts, able to break into or through most obstacles for a team, dependent on level.
Ghost Healer – Someone who can focus on mild healing for a team, uses a digital touch pad to evaluate injuries and restore health. 
Rider - ???

Main classes for Mythics:
Gladiator - A balanced class which specializes in sword & shield with light/heavy-metal armour
Swordsman - A dual-swords user, using leather or light-metal armour and specializing in DPS; their damage threshold is low, their HP moderate, but their regeneration rate for health is quite formidable once started. 
Warlock - A combat-magic user, typically specializing in one or a few specific elements (depending on level and patience for training) including, but not limited to: water, fire, ground, wind, electricity, plant, ice, light, and shadow

Sub-classes:
Cleric - A healer and buffer spell-casting sub-class, often essential for large hunting raids, boss battles, and clan wars.
Rouge - Can unlock most doors (with the right amount skill) without detection and fix items. Has a discerning eye for good items and making plans.
Flyer - A character with exceptional speed and agility, uses a broom or cloud for transport, sticks to long range magic attacks and throwing knives/stars. Only accessible after a certain level.

I think we're on the right track though I'd rather like to see the Mechanics more into sleek sci-fi tech, rather than just toting varying guns, that seems more "steampunk" or something, I can't really think of the word. But I more imagined future weapons, touch interface perhaps for executing? I dunno. I'll keep thinking. I just don't think we need too much of a focus on weapons, since we should also be considering what our characters will pick.