Not to burst your bubble there Nom but having quicker decay rates wouldn't benefit freighters, the paltry 20 seconds between trade lanes isn't going to be cut down by an extra 2 seconds of cruise.
I've flown a freighter from day one of joining Disco (not the same one obviously but I've always had one) and I can tell you straight, the freighter doesn't need an overhaul, it needs a damn purpose but forcing the entire range into some half-baked combat role is absurd. This is a line built around cargo, from the very name to their original purpose and design.
If the dev team don't want to go that route then I'd respectfully ask that your efforts go elsewhere.