I heard that Grim Resolve is BS3. But I haven't seen it in text, so I don't know. However, the Lion's Blade (the Gladius) gives full BS Overwatch in that detachment.
I'm kind of excited about the flier revamp. The Nephilim is now a flying vidicator. S10 AP2 18", and if you roll doubles on the scatter it's a Vortex. BigBaddaBoom. Dark Talon missiles are now S7 and have Missile Lock again, so you can reroll misses. Oh, and I think Strafing Run?
Still love the speeders more than anything else. But I've always been a Ravenwing person more than Deathwing; I think they did better in the end.