From the article the Stryker can’t handle the recoil.
So does it end up on its side with the gun in the AA role?
Which means that ANY vehicle light enough to meet Army requirements would not have the mass to cope with a tank gun's recoil.
Years ago Oto Melara and the Israelis developed a very high velocity 60mm gun that fired discarding sabot and HE. Possibly a weapon like this could be used on Strykers and Marine LAVs. 60mm with a 2 lb charge should be effective with mg nests and the like. The APDS could deal with armor. The recoil should be within limits.