the 4th and 5th gears on the acura are almost identical
and the 4th gear is to high, why didn't they make the fourth gear lower? a lower 4th gear would make the car significantly quicker.

 

This is done for fuel economy. The 3rd gear is good for accelerating up to 110 MPH or so, which is way faster than the typical driver would go.

The 4th and 5th gears are both (very tall) overdrive gears. The 5th gear provides great economy, and the 4th gear gives a very slight increase in power, just enough to cruise past another car on the highway.

I like the arrangement, cause I appreciate the fuel economy. You can always downshift to 3rd for extra oomph.