Needs moar Gloom.
I love DM/SR, I have a scrapper and a brute. They are both very fun to play. I can't look at your build here at work ( no mids ) but I will take a peek when I get home. 
Scataloni Volt
Scataloni
Scataloni Tank
Scataloni Arrow
Rad Scataloni
That build looks pretty solid, of course I would do it a little different but everyone can say that. Im not a fan of purple procs so those would go and put the slots elsewhere and I would slot your heal with 3 Golgi's and 3 Nucleous Hami O's.
The Hami's will greatly improve your heal and the damage will remain the same. Happy AV hunting its a ton of fun.
Scataloni Volt
Scataloni
Scataloni Tank
Scataloni Arrow
Rad Scataloni
Couple goals I'm going for on this build. Soft capped defenses (which I did and then some in case I get what minimal debuffing I might), enough global recharge for perma hasten and MG -> Sm -> SL -> Sm, no endurance issues, and AV soloability.
I initially went with FM/SD, but I found I wanted a heal of sorts and went with DM. I plan on getting the spiritual alpha and the barrier destiny for max resists. I know some swear by gloom, but I wanted to have no worries with endurance (if this is redundant please say so and I'll try it both ways). I *think* I have enough recharge but I'm always open to ideas on how to get more. Touch of Fear is just for fun and the tohit debuff is pretty good.
Tear my ideas up!