First off let me say that I own both. 1 Thunderhawk and 3 Stormravens so far.
Why should I even get any more Thunderhawks?
Thunderhawks and Stormravens are both transports and combat fighters. They deliver troops and a major payload of fire power. So Break down.
Thunderhawk:
Points 920 w/torbolaser
Transport: 30
weapons: 4 x Twin linked bolters, 6 H.K.'s, Twin Linked Lascannon, Turbo Laser or Battle Cannon
Armour: 12, 12, 10
Price: 650-700 dollars

Storm Raven
Points: 200
Transport: 12 & a Dread
Weapons: Twin melta or HB, Twin Las/Assault cannon/plasma cannon, 4 blood missles
Transport: 12 & dread
Armour: 12, 12, 12
Price: 66 dollars

Why should I buy another Thunderhawk when it's easier to put together and more reliable on the component shapes of the Stormraven then a Thunderhawk. I could buy more Stormravens for every Thunderhawk. 4 Stormravenss at least for 1 Thunderhwak.
For the points cost of one Thundehawk I can field more troops with Stormravens.
I can have more overall fire power with Stormravens for the point costs.
Target allocation: 4 targets for one with the Stormravens to Thunderhawks.
Armour: Holy crap the Stormraven has a better armour stat then the Thunderhwk.

Why should I bother any more with Thundehawks? I think GW screwed Forgeworld of further Thundehwk sales. Thoughts. Am I missing anything? What does the rest of the BoLS think.