Extra armor is always a waste of points for blood angels when 15 points has so much better uses.
Dreadnoughts are good, I would note though, they compete for elite and heavy slots which are vital to many ba armies.
Stormravens are in my opinion more of a risk than a land raider since the lower armor and skimmer, but much higher potential with it's mobility and flexibility.
As Ian said, assault squads are much better than tactical squads for ba. For one you get either doa or a discounted transport. Another is the double assault weapon (meltagun cough cough). Oh and ba are at heart a close combat army, so why not be able to get a pistol shot then have 3 attacks at s5 i5 on a charge? Since, I mean, let's face it, you ARE running priests, no discussion of the matter.
Mephiston is very good, watch out early game, as he's got no invul.
Death company are cool, I'm not sure if I'm reading wrong or not, but do not put them in a rhino/razorback/deepstrike. You want them in the action and assaulting, so a sr or lr is mandatory.
Other suggestions in general? Fast vindicators, flamestorm baals, a librarian with shield and blood lance or sanguine sword, assault terminators of either or mixed sorts, (if you run dc) the death co dread with talons in a drop pod (if I remeber right this is doable?).
Hope this helps a bit!