Of course it is possible to improve a strip scar, but it is not possible to eliminate all the problems a strip procedures causes.
The complications include the scar itself, the color change of the scar, and the alteration in hair growth angles.
It is possible to minimize the width of a scar with a scar revision many times, but not always. It often depends on the original width of the scar and the healing characteristics of the individual patient. Some patients have excellent healing characteristics and are prone to finer scars to begin with. These individuals have the greatest chance of improvement with scar revision. Others, especially those of Mediterranean origin and those with loose skin are prone to wider scars and may or many not benefit noticeably from a scar revision. In my hands, i have generally been able to make a scar 50% better, but there is always the risk it will be the same width or wider. I've not experienced a wider scar, yet, but that is always a risk from a scar revision.
The color tends to stay the same (lighter or red/pink) with a scar revision. Sometimes a revised scar will be pink or red, whereas the original scar was white. These color changes can lead to a contrast between the normal skin and the strip scar.
Grafting the scar with my version of FUE has resulted in improvement in the appearance of the color problems. White scars tend to take on a more normal tone, while pink or red scars fade and tend to take on the normal appearance of the surrounding skin. I think this probably results from the deposition of normal dermis and melanin from the follicles into the scar.
The one problem you cannot resolve is the change in hair growth direction. Hairs below a scar tend to be elevated, while hairs above the scar grow more acutely. Often times the angle of growth along the x,y axis (right to left) will be different on the top and the bottom of the scar. The only way to resolve this is to pick up the individual follicular units and re-direct them in a more normal or natural direction. The best way to avoid this alteration in hair growth direction is to avoid the strip scar altogether. This is my preferred method.
A single strip will produce much less alteration or distortion of hair growth direction, but with repeated strips (including trichophytic closures) this distortion becomes a progressively greater problem for the patient.