Tomb Kings in space is right on the money! I don't like that too much, but I'm forcing myself to at least accept it.
Most Necrons are still as they were, the 'new' units having a bit too much awareness for my liking, but they don't make the majority population just most of the pictures!
The Phaeron Characters have taken the place of the C'tan, some are quite interesting. The C'tan are mediocre monsterous creatures and nothing more.
Necron Shields on ships is in the codex. A 6+ hull with shields up and a 5+ hull with shields down could work. (armour is determined for an entire attack, don't roll one dice at a time).
Necron AC is a new notion, Tomb blades, Scythes (fighters, which can have portals) and to a lesser degree scarabs could be employed. Tomb blades are bombers (maybe fighter bombers), Scythes are fighters with the possibility of H&R's (as they'd have to drop troops onto the hull...) Maybe Fighters that can act as assault boats when an enemies shields are down.
Scarabs are just too slow to be anything but mines or CAP (or a refit).
The
motives of the Necrons has dramatically diversified, some want to wipe all life out, some want to enslave, some want to fight other Necrons for political gain, others are just trying to wake everyone up, and some are trying to become flesh and blood again.....
There is also the
Flayer Virus, this makes normal warriors into flayed ones. This could be represented in BFG as having +1 Boarding modifier when you have a normal leadership of 6 (or 7 if 7 is the lowest), you would lose this if you gained leadership in a campaign.
Cheers,
Ray