Fire/DM Stay Ranged or combo Dark Pit w/ Opp Gloom?

I have a baby Fire/DM Blaster that I am trying to decide where to take.

I know I want Soul as my APP because I want Soul Tentacles and Night Fall and it fits thematically. What I'm really wondering about is whether or not it's worth going for Oppressive Gloom to combine with Dark Pit for a high level stun. In theory this sounds like it would work great. I would need lots of recharge and accuracy to make Dark Pit worthwhile.

The problem being I would have to live in melee mode, which sorta defeats the purpose of having those cones.

I was wondering if anyone out there has tried these combos and can comment on it for me.

using OG to stack stun magnitude works well. I use a similar strat on my dark miasma toon stacking OG with Howling Twilight for the mag 4 stun.

I'd say Nightfall is overkill on aoe since your primary is fire, and I'd only use Soul Tentacles for the immob (slot it for damage though, unless grabbing set bonuses). You could probably do something like Soul Tentacles-> Fire Breath while jumping into melee->Dark Pit while OG triggers->RoF/Fire Ball. If you are worried about alphas, you could lead with dark pit and use soul tentacles while jumping in for OG to go off, then use RoF/Fire Ball. if needed you can jump out to use Fire Breath, then jump back in. Being able to use Cones quickly while moving in to a mob will make your toon alot more effective.

Just cause you have cones doesnt mean you have to stay at range, especially if you're using combat jumping you can easily use your cones as you are running into melee, then use your Fire Ball and Rain of Fire while you are in melee. Everything should be pretty much dead at this point sans bosses which will be stunned. At this point you will want to be in melee anyways so you can use Smite and Midnight Grasp to down bosses faster.