Tar pit helps slow those mobs down approaching you.
Holwing twilight is great stun.
Slot up FS and fluffy as best as you can.
And for DP, you using the KB of the attacks or turning on swap ammo? KB is another great form of control to keep those tasers away.
Also, check the difficulty to see if too many mobs or too high level. May need to adjust one or both.
Having level a lot of support toons, red and blue, I know what you are feeling.
Quant: You're not wrong about the stun. I will now go through what workarounds I know.
Something that helps on the "layered defense" is to have more layers. Stun is [sort of] a layer, Fluffy autohealing is a layer, Defense is a defense, and stacked ... what's the one that gives stealth and resistance? The resistance from that one's a layer. [Fluffy does stack that with yours? I'm not that solid on Dark Miasma.]
Check this one because I'm not that solid on the set: I think the Fear from Dark is, in addition to being a great Fear, also a great acc debuff. And it's a click debuff so if you DO get stunned it doesn't disappear immediately.
Mini-guides: Force Field Defenders, Blasters, Market Self-Defense, Frankenslotting.
So you think you're a hero, huh.
@Boltcutter in game.
Also, if Fluffy has dropped, resummon him in the middle of the next pack. Then he tanks for you 
Orc&Pie No.53230 There is an orc, and somehow, he got a pie. And you are hungry.
www.repeat-offenders.net
Negaduck: I see you found the crumb. I knew you'd never notice the huge flag.
I have a Dark/DP defender who I solo a lot (I'm up at weird hours). He was doing fine up until level 40 or so, then... STUN! STUN! STUN! Malta, Freakshow, Carnies... everybody seems to do stun, and a lot of it. The thing that sucks about it for me is that I depend on a layered defense of about 25% positional defense and 30% to-hit debuff from "Darkest Night." But... I get stunned... Darkest Night goes down... I am pulp.
I carry tons of break frees, but the gangs I'm meeting now... I just can't pack enough.
All I can think to do is mez back. Black Hole on the worst mezzer. Fearsome stare for the minions and weak-minded Lts. Suppressive Fire and/or Petrifying Gaze for any other lingerers. And Fluffy, of course. But all that means a respec to grab ALL those mez powers (I only have Stare and Fluffy right now), and tough choices.
Does anybody have any alternatives or other advice? Any temp powers or powers I'm overlooking? Thanks.