That 30 mm does not have a flat trajectory with its relatively short case without a neck. Also regular armorer skills are not transferable to maintain it. It requires a specialized technician to put back together and time properly. No way the guy shooting it or his buddies will know how to fix it in the field like he would the M2 unless he holds a dual Infantry/tech MOS.
What if we doubled up and put two M-2’s on a humvee mount. They used quad 50’s in Vietnam . Also redesign the ammunition to include exploding shells in the belt