engineers are those with the almost supernatural ability to concentrate all their attention in a ridiculously tiny part of a problem and focus on it for days, months and years tirelessly. and still completely miss the context of the actual problem.
an sure you need them to get shit done. sure they will ask tons of money for it, and sure they very well deserve it! but they might need extremely close supervision and strict direction in order to not get lost. remember, focusing in details is their thing, not seeing and understanding the big picture.