The roots look healthy but the dark coloured crown worries me...
I've read that wrinkled leaves are a sign of dehydration and often happens when there is root rot; since the roots aren't healthy to absorb water for the plant.
I've also read (and it's worked for me) to treat a plant with a fungicide when there's root rot. There are instructions on the label for dilution, and the books I've read advise to soak the plant and/or treat the wounds (cut root ends) with the fungicide.
I'm sorry I can't be more help but I'm sure you'll get many more responses from people who know a lot more than I do!!