Viacoins main selling point was 'The most technically advanced coin', there haven't been any commits to the git repo since February and it isn't being kept up to date with bitoin core, in fact it is now two versions behind
I remember seeing that Viacoin was built on top of Bitcoin 0.10. Bitcoin is now at 0.12 and soon to release 0.13. There are lots of new features in Bitcoin now so if Viacoin could build on top of a newer version we could get those benefits.