Disclaimer: I haven't checked the points cost of all these units for accuracy.
That said, this is actually a fairly well thought-out beta strike list, but there are a few possible problems.
First, they changed the way grenades work in assault in the recent Draft FAQ. If they don't change in back in the final draft, then the swooping hawks are going to lose a lot of their value.
Second, it seems like between the dark reapers and striking scorpions you'll have some decent saves, with presumably 2+ cover saves on the scorpions and 3+ armour on both of them while you await the arrival of the falcons carrying the fire dragons. That said, they're still T3, so they'll fold under weight of fire, especially against something like Tau that can potentially ignore cover on the scorpions.
My suggestion would be to consider adding the "disciples of Vaul" choice to your pale courts battlehost to add some T7 vaul's wrath batteries to your army. This will give you some much needed staying power to ensure you don't get tabled while you're waiting for your falcons to arrive. 2 units of vibro cannons and a unit of shadow weavers would basically replace the offensive roles of the hawks and the spiders, albeit with static gun positions.
If you wait to find out what they're going to do with the grenades ruling and they rule in favor of multiple grenades in assault, I'd probably withdraw my suggestion and say the list is pretty solid as-is.
EDIT: Finding a way to put a wraithknight or D-scythe wraithguard into the list might not be a horrible idea. My question to you is this: What are you going to do against a wraithknight? The most simple solution is another wraithknight, or D-weapons, neither of which you're currently running.