I'm not sure about the raveners. You do have a pair of flyrants to run backup and synapse for them, and 5 of them packing rending claws is some serious heat. However, that could also easily prove their undoing (although there's a lot to be said for their absolutely blistering pace.
I think they need playtesting more than anything else. I also think it's worth testing to see if it's worth going for biomancy on at least one of your tyrants. Iron Arm can turn a flyrant into a seriously tough cookie, and can potentially help reduce the impact of being grounded, as can Endurance, while Warp Speed makes them really scary combat opponents regardless of what weapons they have.
Overall though I think it's a perfectly fine list, although as mentioned the ymgarls might be a little unwieldy. If you drop the raveners I think I'd look at replacing them with another hive guard brood, as right now it's a little too easy for your opponent to neutralise your anti-armour units.