When Pothos vines are not pruned regularly they inevitably start to lose older leaves and become leggy. Occasional watering lapses, age, and inadequate light are the most common causes of this leaf loss. Older leaves are never replaced. New leaves always emerge exclusively at the tip ends of the vines.
To eliminate legginess, it is best to prune the vine all the way back to its oldest leaf so that all or most of the leafless section is removed. New leaf growth will emerge on that vine starting at the point where you prune it. You can't do any damage by pruning a stem all the way back to within a couple of inches of the soil. Pruning is a great (and only) way to rejuvenate a leggy vining plant.
Pothos tip cuttings root most readily. A tip cutting with about 4 leaves and one bare node at the end to insert into water is best. Long cuttings do not root nearly as readily. It is best to root multiple tip cuttings together.
I am concerned about your repotting. The soil, pot, and roots were not the cause of the leaf loss or legginess. Much can go wrong if repotting is not done correctly. The chances of root damage and inadvertent over watering increase substantially after repotting.
