I'll post my thoughts on this matter, and we can have meaningfull discussion.
1. It is interesting to note that Worf said 'Sheilds down' 3 times. Does this suggest he was able to get some level of sheilding back up in time?(The Husnock warship returns and approaches to within 5 km again)
PICARD: Lieutenant Worf, open a hailing frequency. Warn the vessel to stay clear of the planet.
WORF: Aye, sir. But they are already within firing range.
(The Husnock ship fires)
WORF: Shields down! Captain, they hit us with four hundred gigawatts of particle energy!
PICARD: Damage?
WORF: Superficial -- but I am having trouble reassembling the shields!
(The Husnock ship fires again)
WORF: Shields down! There is thermal damage to the hull!
DATA: The warship is in possession of enormous energy reserves. It is capable of striking us with far more powerful bursts.
WESLEY: They're maneuvering to come between the Enterprise and Rana Four.
PICARD: Number One, we have been exemplary in our patience.
RIKER: Lieutenant Worf, fire phasers on full with a simultaneous spread of torpedoes.
(The Enterprise finally returns fire)
DATA: The vessel appears undamaged. Its defenses are apparently able to absorb incoming matter and energy.
RIKER: Commence rapid fire with all weapons on full!
(The Enterprise unloads on the Husnock ship, with a nice display of at least a dozen torpedoes and a similar number of phaser blasts. The Husnock ship returns fire and numerous bridge consoles erupt in showers of sparks)
WORF: Shields are down! There is internal damage -- weapon systems control has been lost!
RIKER: Riker to Sickbay. Medical assistance to the bridge!
PICARD: Mister Crusher, move the Enterprise out of range of the attacking vessel!
2. In the second volley from the nasty Husnock, lets say that the energy did hit the hull, as suggested by the dialouge. Worf may have just said 'shields down' just to remind them he hadnt fixed them yet. Anyway, that energy bolt only did thermal damage to the hull. Thats pretty good considering how thin and how dotted with windows the GCS's hulls are.
3. This exchange demonstrates the GCS's impressive rate of weapons fire.
4. In the first shot that broke the E-D's sheilds, he said 'Particle energy' as opposed to pure energy. It is possible that Fed sheilds are vulnerable to this particular type of weapon. Pure energy of the same level may not have been as damaging.
5. Again, it is odd that Worf says 3 times that the shields are down. Any theories?
6. Worf said something about 'Reassembling the sheilds'. This sugests that he could have re-raised the sheilds fairly quickly if he had not had trouble.
Well, I'm done for the moment. Thoughts?
EDIT: Spelling errors.