Well done on getting new list up AoC.
I will echo everyone regarding the Hunt for the Fallen rule. It just doesn't fly. At the very least you need to give the choice to your opponent as to which formation has the Fallen in it. This will make it difficult to gain that BTS as it should. Otherwise I think the Hunt for the Fallen rule as written is broken.
I would suggest something like:
Before the game begins the Dark Angels' opponent must choose a formation from his army to contain the Fallen Dark Angel or a close associate. That formation now counts as the Break Their Spirit objective. The requirement of destroying the formation with the highest cost no longer applies as the Break Their Spirit objective. If he puts it in his
toughest formation... well, no one said the Hunt for the Fallen was easy....

Nephilim.... Could we truly not have just gone with 2x aircraft to begin with...? A bit OTT even with the restriction of tying them to the Ravenwing. These are pretty much the best fighters in the game now. The Heavy Bolter could easily be toned down to a 15cm attack for starters.
Structure - I agree that non-core could/should be more accessible but let's see how it pans out in testing.
Assault Terminators - Re-inventing the wheel? Now any other list with them has to change. Otherwise re-name them. Also, they should actually still be +1EAMW as the basic CC weapon would be MW statted. As written they get 3 CC attacks and should lose their Invulnerable save as they don't have Storm Shields. Why do I feel like Assault Termies should be ditched in all lists and just stick with standard...?

I guess we see how they work out....
I like the new Ravenwing set up.
A few typos/grammaticals etc:
Ravenwing - All Bikes, Attack Bikes, Land Speeders (All Variants) have the Scout
(-s) ability. Bikes have Teleport Homers which allows Terminator
(+s or units) to re-roll a failed Teleport test if within 15cm.
Unforgiven - The Dark Angel
(+s') dark secret is their
(')s alone
(.) No Imperial Allies can be taken in
(a) Dark Angel
(+s) Force.
The Devastator stat has only 1x Missile Launcher. If they're standard Devs it should be x2.