Opinions needed.

Well obviously slotting them for damage is going to double their damage output. They aren't the most damaging anyway but Dark/Time kinda needs every bit it can (at least mine currently does) and once summoned it's basically free damage so I'd never drop them.

What is the alternative power you're thinking of picking up instead?

Well atm I don't have any spare slots to give to them that's why. Also once I got the umbra beast they kinda took a backseat because I was never worried about summoning em (this was after umbra beast was fixed heh) I guess the main reason I am thinking about dropping them is because I team with 2 other people one being a brute and the other another troller. I never really solo'ed with them. The other power I was going to get was invis that way it'd be easier for me to zip to the end objective in missions or something else that would just help us along.

For invisibility: Consider using Super Speed as your travel power, and put a Celerity Stealth in it. That gives you full invisibility and a travel power all in one. Drop your current travel power. If you need verticle travel, keep a Raptor Pack on hand (buy one for 10K Infl in the Shadow Shard or in Grandville, or you can get the recipe and craft it, or you can get one from running the Positron TF, Part 2, or even the level 5-10 Police Band Bank mission). There is no need to waste a power pick on invisibility.

Haunt is a nice source of damage for a low damage controller, but just as importantly, they provide a form of distraction to keep you from getting hit -- expendible pets are great for taking the Alpha Strike. They chase down foes you may not see. They can sometimes hit foes you can't.

If you don't have slots to slot up Haunt for damage . . . then your build probably needs some work. Haunt is one of the better powers in the Dark control set. They can be used much in the same way that Phantom Army in the Illusion set can be used . . . but they aren't invulnerable. They are a "use them whenever they are up" power.