The third sub class slot is the skill tree for space combat (Destiny)

by Dan de Board , Tuesday, April 14, 2015, 20:00 (3517 days ago) @ Kahzgul

A lot of what you mention is already represented in the game in some way shape or form, and I think for a lot of them it would be difficult to build a whole class around them with the way that talents, abilities and supers work. A few ones that stand out that I'd like to see:

Illusionist/Decoy class

Only if the super is the decoy and it explodes. This would probably make a really cool Hunter sub-class, though I'd be worried it'd be too similar to the Bladedancer in terms of sneakiness.

Vengeance class (damage reflection and redirection)

This would be super fun, but might be really broken. I imagine this most as a Titan, probably running around with that fiery axe everyone loves so much.

Engineer class (turrets etc)

Very good for defending those points. I could picture three variations of the turret: invisible weaker one, strong slow firing one with AoE (like a boomer) and maybe a melee turret? Warlock makes the most sense for this.