In this case the acquiring company made the right call, the acquired company executives were trash.
So were McDonnell Douglas's.
I've heard aerospace companies have standing checks in place to ensure that they never go above being composed of more than Y% ex-Boeing employees be it management/design/floor workers so that they don't end up with the Boeing 'culture' creeping in.
Or you can do the opposite, like Boeing did: import all the managers of the firm you acquired (McDonnell-Douglas) into your own organization.