Something I found potent were Jump Pack
DC with a screen of Bikes. The bikes provide mobile cover, and are excellent weapon platforms for Grav, for example. If the bikes are shot, Jink. If the
DC are shot, take a cover save followed by the
FNP. Or armour saves, of course.
As for the
DC themselves, I made slightly larger units to allow for casualties on the way in. My blend wasn't "ideal", as I built 8 models with a
PF, Thunder Hammer, and a Power Sword... it worked out not too badly. If I charged basic infantry, the Power Sword guy generally chopped up a few dudes before they could attack [Higher Initiative Detachment] and if I attacked something "big" he was usually just another casualty, though he would occasionally manage a 6 against
MC's.

I personally like the versatility that the power sword offered, but I like multi-role units, and am willing to sacrifice points towards that. Different strokes for different folks.
That said!
I've found running my
BA as Vanilla Marines let them be better at doing an assault army. Use your
DC as Vanguard Vets, or without jump packs as Honour Guard. If you have a lot of
PW mixed in, that is.
The only thing I would suggest putting in a Storm Raven is a "cheap" Dreadnought, or something with an impressive Invulnerable save. If you only have the one bird, your opponent will focus on bringing it down because they'll get a 2 for 1 kill. Remember that when you crash, everything inside will *probably* die. Unless they have a good Invul.
5x
TH/
SS Termies in the Raven is a big gamble, but it can pay off if you can drop them onto a Wraithknight after shooting it up with some grav-bikes, the anti-tank weapons on the SR, and then simul charge with some Death Company. I've managed to pull that off, and it worked quite well for a two-turn kill.

Still lost the game... damned Scatter Bikes... but it was close.