Well I don't really care about what fluff says about the "real dimensions" or "science" of any of the ships or ordanance of this game because its all hokey and stupid to me. Super-megalomaniac-laser-plasma-gun-of-doom means nothing to me.
I'll speak in relative terms though. And in relative terms, a squadron of bombers plasters multiple areas of a ship where the Caestus hits one spot each, the spot that it eventually rams itself into (thereby, only creating one hole per Caestus). By comparison, each Starhawk plasters around what, ~20?, areas of a ship? That is not even close to a comparison in terms of damage output. It would be like saying the Hs-129 German ground attack plane was more effective than a Ju-87 Stuka because it had a bigger gun.
Look at it this way, the Ram will fire a shot into the enemy ship right before impact and then smash through it, and release it's small complement of troops to cause havoc (essentially, having the jump on the defenders). The Shark/T'hawk will slowly approach it's target, bore a hole through (giving the enemy time to react), and then offload it's much much larger complement of troopers. To me, this balances out. It should play the same.
-Zhukov