We're talking about the "suppress two zones instead of one" rule, yes?
I think it's fine, but highly situational, because in addition to a high-Availability minigun it requires targets in two zones (and enough of a game map to know that they're in two zones).
In order to make miniguns less situational, what I would have liked was a rule to upgrade the suppressive fire in a single zone. Options include:
1) Cover a single zone with enhanced suppression, per Run & Gun;
2) Require two successful and separate REA+EDG defense tests by defenders who don't drop prone, or make the defense test a single attribute (REA or EDG), or something else to reflect twice the bullets in the same space; or
3) Let the attacker's net hits stage the suppressive fire damage.
And so on. To me, those options seem useful without being game breaking, especially given the Availability of miniguns in conjunction with the cost of burning 40 rounds per Combat Turn.