Is technical director more effective than head coach?

[Kohli_Sox]

Ravi Shastri and Khaled Mahmud both are technical directors and mediocre players. But it seems like teams gel together under them more than other head coaches. They seem to form good partnerships with captains eg Shastri with Kohli and Shujon with Mash/Shakib. The point of this thread is to discuss that if technical director with specialist batting/bowling/fielding coaches is more effective method than employing a head coach.