Can you explain your intended workflow if you had this super sized Curves panel? How about if you use the Hand icon from the Curves panel to target a particular tonal value from the image, which will place a point on your curve. Then use the up and down cursor keys to adjust the Output values, and left and right cursor keys to adjust the input value. You don't need to select those values before adjusting them. Just use the cursor keys.
If I use the hand tool in the curves palette to select a point for manipulation, that works fine. But if I need to manipulate a point on the curve that is very close to the original point, Photoshop wants to "join" the 2 points. It does nto allow me to manipulate areas on the curve that are too close together.