Brain fart
Agreed, no more than the mounting of the M55 .50 multiple gun mount, or the similar twin .50/37mm autocannon Maxon mount in the WWII M20 armored car did.
And just as the Stryker platoon needs to be accompanied by a vehicle capable of long-range engagement of similar hostile vehicles equipped with kornet or khrizantema AT guided missile system [probably a TOW-equipped Bradley] or at least keep the infantry squad's Javelin gunner aboard one vehicle in the team, probably only one Stynker in 4 or one in six should have the quad-gun mount. The rest should carry the 40mm/.50 turret of those Military Police XM1117 ASVs. That'd require less reworking than the fitting of the *bedsprings* anti RPG slat armor did.