Is the Exoddus mechanic of muds changing colour depending on their emotions actually considered canon? Maybe that can explain Abe's growing purple hue, as he gets increasingly tired and cynical
For me the biggest change in the new Abe is the 'nose' section being smoother, i.e. less of a heavy crease in his skin. Whilst I do think he looks more natural, like the skin is properly formed around his skull which has a much more defined shape, he seems to have lost some character.
Colouring, especially lighter and darker areas, could make things look very different really.