Not so much too powerful since the surface is sized to provide the appropriate amount of force.
One of the arguments for an all moving surface is that the surface can be smaller, thereby reducing drag.
The problem is that the movement of the Center of Pressure vs. the pivot point changes as AoA is changed.
Increased AoA causes the CoP to move forward and can cause a reduction in the control column force with increased movement. It's even possible for a design to have the CoP move far enough forward that the surface has an uncommanded movement and 'locks' into a fully deflected position.
The generally desirable feedback is an increase in control column force with increased surface deflection. Uncommanded movement isn't exactly welcome either...
A tab is used in these cases to cause a restoring force, increasing the control column force needed to move the surface with increasing deflection.