WillC said:Your Pothos is a hybrid and the coloration can change for reasons beyond your control. Just keep it healthy and let it do its thing.
The root system you described is exactly as it should be and it does not need to be repotted. Plants do best when kept moderately potbound as yours is.
Give it lots of bright indirect sunlight, close to a window, but just beyond the reach of the direct rays of the sun.