Horizon,
This is one approach (although I would say minimum 1 squadron per cruiser, recalling somewhere in the rulebook where it says few ships go into battle without a
pair of Swords at their back... probably in the Sword entry...), but it would be ideal if the compulsory inclusion of escorts had a good, sensible reason.
After all, if escorts are best at independent roles like flanking enemy fleets and most people would rather take another cruiser instead of an escort squadron, why would the Imperial Navy even use escorts as escorts in the background? I definitely agree that some escort classes should (and do) perform these vanguard and gunship roles but I think the 'escort function' is lacking and that this could make escorts an attractive choice for fleets which should, thematically, have them (besides the fact that escorts are one of the key aspects of the game

Therefore, I have a rough idea of how the types of escort would work. (1) Gunship escorts. These are the current escorts and are good at killing big ships/doing the stuff that they do now. (2) Protective escorts. These are bad at killing big ships but are good at providing escort bonuses to capital ships; I think it would be a bit militarily pointless for an escort squadron to just provide shield reinforcing so I think that the Protective escorts would need to have anti-ordnance guns too (also reduces the number of semi-redundant ship classes). It strikes me that Protective escorts would be kind of like defensive monitors (they wouldn't need to be particularly fast, for example).
E.g. '
Escutcheon Class Frigate'.
Light Tracking Turrets: Uses reversed gunnery chart, 3 firepower weapons batteries (for example).
Massed Shielding: Any capital ship with two or more Escutcheon Class Frigates in base contact receives +1 shield value, to a maximum of 6 (and the escorts gain +1 shield?). Only one shield may be gained in this manner. If a frigate providing shielding is destroyed, the blast marker must be placed in contact with capital ship.
Blurb:
The Escutcheon class offers additional resilience and ordnance defence to any escorted capital ships, but if they are destroyed the escorted capital ships can be weakened significantly. Another idea: Massed shielding allows any ships in base contact to avoid placing a blast maker on a 4+ (i.e. old Necron shields + normal shields)? Avoids the problem of escorts getting very resilient with additional shields and stops them from being picked off without them.
I'm not sure if there is any reason why gunship escorts couldn't be protective too, from a background perspective; perhaps they have different shield systems?
AndrewChristlieb: I agree with your turret suggestion, but I think it should be stipulated that the escorts must be in squadron cohesion to benefit, a convenient way to reinforce the tactical importance of cohesion.
Thinking Stone