I must disagree with you, skippy01 (cool name, by the way).
a) I think that it is more likely that escorts are required in BFG for defence; for a start, they're called 'escorts'. If they can't stop ordnance or protect ships against firepower, how exactly are they 'escorting'? The only escorting role they have now is to be a cheap amount of firepower (at least in theory) that is annoying to destroy because it is not a more valuable target.
b) I also think that people usually draw too much on WWII tactics when thinking about BFG! Here, though, I think it supports my position. In this case, I think the combination of the more manoeuvrable and smaller escorts taking up a position around a larger ship would generate such a 'wall of fire', although it would be more of a tactical field of fire potential (since filling up the area with a real wall of fire would be senseless in space).
c) In response to Phthisis, another point is that an escort is around 500 m long (ish), or even longer. A bomber is much smaller, maybe 10 m. Why would a naval commander (even a dodgy Imperial one) take escorts when a ship 50 times shorter could easily squish it? I think it is more sensible that a naval commander would rather big guns on survivable cruisers and battleships (otherwise, why create large ships in the first place?) and have the escorts take on a protective role, as well as fulfilling a gunship-oriented role if necessary.
In conclusion, in almost every tactics/points-related posting, I see people struggling to appropriately value escorts. They just don't seem to be worth it in most situations! I think that making escorts have a more anti-ordnance protective role not only reduces the unlikely 'suicide' factor against ordnance but also gives them a proper role in the field of battle.
Perhaps escorts should be redone into actually being large groups of attack craft? Could be an interesting prospect (although not brilliant, I'll admit. If only Sigoroth would comment....).