When a surface feels too sensitive you've got two problems.

The first is that it's too sensitive. Yeah.... It's going to be hard to steer. But everyone knows that. But it is able to give full effect with it's movement without moving much AND your transmitter stick is going to be too "powerful" to be of much use. Exponential does a bit to help. But the best way is simply to match the full throw that is needed from the surface, which is obviously less than the mfg's recommended throws, to the TX stick's movements. Best way to do that is change the servo arm connection point IN on the arm. That way, your servo gets a bit of leverage help. It'll draw less juice and have boosted force from the leverage. No cost, no effort. You get the same result by moving the pushrod connectio OUT on the surface's horn. Whenever you move your throws away from 100% in your TX, you're reducing the accuracy of the stick's control. No need to do that when it takes less time to change a pushrod connection.

But the real killer from a too sensitive control isn't so obvious.
If the surface is too sensitive it tells you something. That surface can be a killer. If it's only taking a very small deflection to be tricky to steer, what do you think it's going to do at full deflection. And if that full deflection comes suddenly? It's going to stall that surface too easily. One aileron stalls, what happens? (The downgoing one at low speed almost always can stall that side in a heartbeat.) The elevator stalls, what happens? None of those things do you want when trying to recover a model that's low and slow and going where it wants to go instead of where you thought it would go.

So when a surface is too sensitive, it's telling you to either reduce it's throws or...... Work on tuning your low rate deflections to give you safe flying deflections. Then use the 100% high rate (you don't want high rates more than 100%) for snappy, tumbling maneuvers. And use a 60% or such low rate for smooth maneuvers like 8s and such. And ailerons at low for takeoffs and landings or whatever works for you and the model.

We got some awesome stuff nowadays. But sometimes it's the killer, not the helper.