I don't really know how big of a dent a particle blaster could create : /
The weapons are considerably few and small, I agree. However, it is not a ship ment to overpower an opponent, but to outmanouver him throught sensor jamming and electronic superiority. This is why it has so many sensor arrays on top.

If it was conciplied for firepower, I'd have given it 20 guns and missile bays that shoot additional guns.
Overkill is a myth.