Skip over the skill gap

I'm working with several managers who have poor communication skills, over-controlling behaviors and ineffective use of the tools at their disposal. Training them in their deficient areas didn't work. What should I do?
Forget about fixing them. They're problem may be feeling pushed from your trying to eliminate their skill gaps. They may have even developed self-concepts as "managers who need to be pushed" and will rely on your constant pressure to change their conduct. You're feeding the problem by trying to solve it.

Are you advising outright neglect of their skill gaps as way to pull for these ineffective managers?
No, I left the other part unsaid to pull you deeper into this discussion. I recommend selling the people who will benefit from improved management. Help these managers' direct reports see how their work lives will be easier, more productive and more satisfying when their managers communicate better, use less-controlling approaches and make more use of the tools. Skip over the skill gap and show the people affected by the mismanagement what to expect differently.

How will that pull for the ineffective managers?
When the managers get the impression that their direct reports: want to be managed better, expect the benefits from it and foresee the improved work experiences, a demand for change is created. The managers face a new opportunity to make a difference and an opening in a wall of obstacles. They feel pulled into the new possibility instead of getting pushed into fixing their same-old skill gaps.

Why won't they feel you went behind their back, undermined their authority and set them up to look inadequate by selling their subordinates on the benefits of changes?
You're describing managers with high control needs and a very low tolerance of ambiguity. You're right that "control freaks" will take it wrong if you create space for them to fill. Their skill gaps are deeply unconscious and inaccessible to the effects of pulling for them. Anything they do not oversee appears out of control, dangerous and antagonistic to them. They need therapy, not training or a contextual change from pushing them to pulling for them.