We may just have a base philosophical disagreement here about what a weapon quality should do. I’m more inclined to keep it within the scale of what a weapon quality typically is, but if you find it preferable to work outside that I’ll see what I can do to help.
Blanket Barrage struggles to translate because of how damage scales in personal scale vs. planetary scale. Half damage with a turbolaser will do a nasty number on your starfighter, but half damage of a blaster rifle vs. a stormtrooper is 0 Wounds.
Here’s a suggested rewrite, partially based on a “special attack” I made for the system I’m building: “The character may attempt a Hard check using this weapon’s skill against a target within the weapon’s range (this check is not modified by cover, but concealment still applies). If successful, the target and all targets within Short range upgrade the difficulty of their combat checks once, plus once per 2 Advantage. If a target generates 2 Threat or a Despair, it suffers a hit for base damage plus net success.”
I further extended it to include movement using mechanics built into the system. The tricky thing with Blanket Barrage being intended for vehicles is that it’s intended to combat fighters, and fighters usually have to get in close to make their attacks, so it simulates training point-defense systems on a fighter making its attack run. In the case of personal-scale combat, nothing forces the target to remain where he is. You could counter that by having a target trying to perform a Move Maneuver roll a Setback die, suffering a hit on a Failure result.
Concentrated Barrage: For this, I prefer your initial idea of it being damage equal to the auto-fire rating. That would affect my answer for the previous version, though. “If successful, the character may spend 2 Advantage to increase the damage of one hit of the attack by an amount equal to the weapon’s Auto-Fire quality.” I think that keeps it more in line with how a quality works, making it easier to remember, and prevents it from getting out of hand too quickly. One of the big complaints is about stacking damage against a single target.
Overwhelming Barrage is very similar to Auto-Fire RAW, except stronger since it only costs 1 Advantage. It has additional limitations and qualifiers, but I’m not sure that really balances it out. You also run into the problem of whether minions count as one target or multiple. Can you hit the same minion group multiple times?
Just for reference, here’s how I handled automatic weapons in my system. I think this is basically what you’re wanting to represent.
Because weapons have “special attacks” they can do, these kinds of actions are wrapped into my rules. The FFG SWRPG is built in such a way that it can’t handle automatic weapons very well.
Same concept, different system
Hail of Lead: Before attacking a target, as an Incidental, the wielder may add the Scattershot quality [spend Opportunity to deal X damage to target Engaged with the first target or to the first target on a miss] at half the weapon’s base damage and expend [additional ammunition].
Mow Down: Before attacking a Flanked target within the weapon’s range, as an Incidental, the wielder may increase the Danger of his attack by one step and expend [additional ammunition]. If he succeeds, he resolves the initial hit and may then inflict a second hit for full damage to the original target or a target within Reach of the original target (the second target must not be more difficult than the initial target).
A Golden Opportunity may be spent to inflict a third hit in the same manner as the second.
Suppress: The wielder may attempt a Tricky (9) check (using the weapon’s skill) against a target within the weapon’s range (this check is not modified by cover, but concealment still applies) and expend [additional ammunition]. If he succeeds, the target and all characters within Close [~10 yards] range of the target are Suppressed until the beginning of the acting character’s next turn and suffer 1 Strain, +1 for every 3 net Success. If a Suppressed character generates a Critical Danger, he suffers an automatic hit.
2 Opportunity may be spent to give each affected character a Complication on his next check made before the start of the acting character’s next turn.
A Golden Opportunity may be spent to increase the Critical Danger threshold of all affected characters by 1 until the beginning of the acting character’s next turn.
If a Suppressed character attempts to move (by the Move Maneuver or some other method), roll a Danger die and increase the Critical Danger threshold by 1 (this stacks with other increases). If it generates a Critical Danger, the target suffers an automatic hit. After resolving this Danger roll, the character is no longer Suppressed.