Artificer (clockwork):Oh and the highlighted ones are ones I had considered myself (Though perhaps you have different ideas)
Could you elaborate on the various builds. Explorer and Titan sounds intriguing?
Has 1 or more clockword companions. Powers leverage the companion. Sort of like the beast master. Possibly I'd have them bundled with "encounter" powers; so instead of taking an encounter spell, you'd get a companion (with its own at-will ability) and an encounter power to use on the companion? That permits you to have more than one if you want.
Warlock (abyssal):
Made a deal with a demon. Demons are chaotic and destructive. Friendly fire AOEs, summons that behave randomly, etc.
Swordmage (dancer):
Possibly the two-weapon swordmage. Aegis of Blades (translates as shield of blades). Immediate interrupt parry attempt (opposed attack roll). When triggered, whenever you attack the target you get an extra off-hand weapon attack on them (delayed punishment).
Wizard (sage):
A leader-leaning subclass. Abilities that are about knowledge checks. Use actions to know things, provide information to allies to buff them.
Bard (explorer):
Indiana Jones/Pulp action hero. Explores new areas, writes stories about them to send home.
Sorcerer (titan):
The Titans are the primordeals who gave birth to the Giants. So lots of size manipulation, raw strength magic. Has limited access to the runes of creation, the language the universe was forged using.