I see the idea is a DOA deathcompany list and wont suggest going away from that, just a few things to make it more competetive.
Firstly Dante is an aweful lot of points and doesn't fit with the death company theme, his accurate DS ability is good but a much better option (and a big points saver) would be to take Lemartes instead.
Lemartes makes the squad much more killy on the charge and once he's taken a wound is probably more dangerous than dante, plus he can't be singled out in combat.
The Sanguinary priests aren't needed in death company squads as they already have feel no pain and furious charge. The only people they are effecting is astorath, dante and themselves. This is alot of points to do very little so dropping these would be a good idea.
On to the death company squads. Firstly I think they are a bit to big, I like 7-8 members plus a character, on the charge this is enough to take out more or less anything. Each squad needs a single powerfist to deal with dreads and maybe 2-3 power weapons depending on preference. Taking power wepons on all members is just overkill, you need some bare bones dudes who can be removed as the first casualties. Death company are so good in combat that they don't need that many power weapons.
The hand flamers are not good here, they are an anti-horde weapon and death company eat hordes for breakfast, plus if you manage to kill a few models with your shooting they can remove the models closest to your squad and prevent you from assaulting due to being out of range.
A better choice would be melta pistols, your main weakness is going to be against vehicles and these give you a good chance of popping them and if they are a transport you can then assault the contents.
The dreads are great
Dropping priests, power weapons and swapping dante for lemartes should give you alot of extra points to play with, here's what I suggest. (don't have my book with me so you might not be able to get all of this
)
If you've dropped a guy or two from each DC squad then you should be able to get a third small squad to give you a bit more flexability, only a fist would be needed on these.
The other points should allow you to invest in an additional dread in a pod giving you an odd number meaning you can get two of them down frst turn. I'd recommend all dreads get magna-grapples as you are still woefully short on anti-tank weapons and this would allow you to fire a melta and a grapple from each dread when they arrive and hopefully take out some vehicles so they can't run away from your DC.
Obviously you maynot have the models for these changes but I think the list would be alot more fun and competative to play whilst still being true to the origional premise.