It seems McFarlane Toys has confirmed that they are currently done with The Walking Dead toy line, at least for now. In a response to a fan question asking about the line on Facebook, McFarlane Toys responded with this:
It has been some time since we’ve seen new Walking Dead figures. The last few 7″ scale solicits were quietly cancelled last year. It looks like they still hold the license, as their banner image with all of their current licenses still shows The Walking Dead logo.