What's your opinion of this interesting take on leadership from the great field marshal Erich von Manstein?

I divide my officers into 4 groups. There are clever, diligent, stupid and lazy officers. Usually 2 characteristics are combined. Some are clever and diligent. Their place is on the general staff. The next are stupid and lazy. They make up 90% of every army and are suited to routine duties. Anyone who is both clever and lazy is qualified for the highest leadership duties, because he possesses the intellectual clarity and the composure necessary for difficult decisions . One must beware of anyone who is stupid and diligent. He must not be entrusted with any responsibility because he will cause only mischief.