Dark and something fun

So, I haven't played Defenders in a long time, and am looking to come back to one. I have always really liked Dark Miasma, so that'll be primary, but I'm having a hard time choosing a secondary. I want something that will let me solo when I need to (not often) and if possible, have some control and debuff something other than To-hit, since Dark/ by itself I feel is strong enough in that department.
I'm considering Psychic or maybe Ice. Both debuff recharge, I believe (not sure about ice), which is something dark doesn't do terribly well, and both have control-type effects. I'm just not sure which is better for what I'm looking for, or if there is perhaps a secondary I am missing that controls a bit and debuffs something other than To-Hit.

Rad works well. Dark needs to hit for some of the powers to work and rad provides a lot of -def. You can also perma stun bosses, not the best damage though.

Ice - Slow Debuff (movement and recharge), 2 Holds
Psychic -Slow Debuff (recharge), Sleep, Disorient, Immobilize, AoE KnockUp
Sonic - Res Debuff, AoE Sleep, Disorient
Rad - Def Debuff, Disorient
Dark - ToHit Debuff, Cone Immobilize, AoE Disorient, Self Heal
Elec - Recov Debuff, End Drain, Hold
Archery - No Debuff, Disorient, No Crash Cuke
Dual Pistols - Def Debuff (lost when ammo is changed), Res Debuff (lost when ammo is changed), Disorient, Slows (Cryo Ammo), Dmg Debuff (Chemical Ammo)

Didn't touch Energy or AR. Never tried them.

If it's between Psy and Rad, i would personally go Psy. The knockup is a pretty quick recharge and you can make the mob look like popcorn on your tar patch.

I have a dark/sonic i love however it has no real "control" when taking on a mob but the resistance debuff makes up for it. Dual Pistol/Dark is pretty effective too if you swap out the ammo. The KnockBack in the normal ammo messes up a tar patch strategy.

I'm going to try to only hit on some points not made above:

Ice - Rain powers (Ice Storm, Blizzard) are blaster level damage. Very powerful over a Tar Patch. The slows stack very nicely with Tar Patch too. Not even counting debuffs, you get mitigation simply from mobs trying to escape Ice Storm but not being able to.

Rad - lots of aoes

AR - Flamethrower + Ignite on Tar Patch sounds pretty cool.

IMO - based on what you're looking for, OP, (control and other debuff) I give an enthusiastic endorsement for Ice. Freeze Ray + Petrifying Gaze means held boss. Freeze Ray recharges so fast the boss will stay held and you can hold others.

Hmm... interesting.
Let me ask a question: Do the Psychic secondary effects trigger often enough for them to be reliable?
/Psychic looks amazing... except for that fact that all the "control" powers only have a percentage chance of going off, and that doesn't sit well with me. I'd rather go for something slightly less powerful but that works all the time. Frankly, that's the only issue I really have with /Psychic or I would for sure take it. All those controls PLUS the mitigation of Dark/ sounds wonderful.
I tried /Radiation once and it was okay, but for some reason it annoyed me. I think it was the schitzophrenic nature of the powerset. It has one of each type of AOE and ST, and I think I just got annoyed with it.
/Ice sounds like a good middle of the road choice. I didn't know it did solid damage, and that IS a factor for me. It doesn't have the variety of control that some other sets, have, but two holds is solid.
In the end, I'm hoping that someone can answer that question about the reliability of Psychics control effects. That would the the final deciding factor for me.

I know you said you don’t want Dark/Dark but there is a reason to go Dark secondary. When leveling you won’t have fluffy till much later and you don't always want to plop Darkest Night on every fight with early end issues and the fast speed of fights. With Dark secondary it gives you just enough -tohit in things like Tentacles and Night Fall to make leveling a breeze ( no down time ) .

5 slot NF and 6 Slot TT ( add 2 Range ) and they both have 60 range with a 5 second recharge. Tar patch >TT>NF>TT>NF so on and groups of 3 to 10 melt in seconds especially if you have solo Vigilance, Assault and Tar Patch. They won’t barely touch you with the -20 tohit debuff stacked from both cones.

There is a reason why Tri-Darks are so nasty at 50, throw in Darkest Knight, Fluffy, IO's, Shadowfall and Maneuver and forget about ever getting a "damage taken" badge

I have a Dark/Arch that is pretty fun.

Pull them to the tar patch using Darkest Night, once they are all bunched up in the patch and debuffed, hit them with fearsome stare, let loose with your rain of arrows crashless nuke and follow up with exploding arrow. Fun times.

I'm having fun with my Dark Miasma/Dual Pistols defender.

He doesn't do a whole lot of damage, but the grab bag of secondary effects meshes nicely with Dark's powers. Cryo Ammo will slow them to keep them in your Tar Patch longer, as mentioned, Chem Ammo will stack nicely with Darkest Night to debuff damage by a significant amount. Incendiary Ammo will increase damage output enough that it starts to feel like you're actually hurting things, especially if they're on a tar patch.

I haven't gotten Fluffy yet, but I suspect the combo will get awesome once he's out and doing his thing.

I can attest to the effectiveness of Dark/ice and Dark/dual pistols. Of course if you switch it around, a Fire/Dark Miasma corruptor is extremely nice, too.

It took me over 5 years to finally level a Dark Miasma, and it took Fire Blast as a Corruptor to keep me going...but if I had to go with a Defender, Ice Blast would be the secondary hands down.