well it depends..

the obvious draw backs of revegging is that the female will grow stress induced male balls, ultimately (depending on how much you've cut it back) will regrow as a hermie. now, this isn't always a bad thing.. as stress induced male flowers can be picked off and even with a few male flowers the seed count will not be large.

Growing re-vegged plants with new plants is.. obviously not a great idea.. as any male flowers will pollenate any other females that you have around.

I think we need more info on your intentions... are you talking about revegging a plant that you've just harvested? or putting a plant that is in 12/12 back into 18/6