I second both the Yasuhara and voice actors suggestions, though for voice actors it might be tricky...I met John DiMaggio earlier this year at a convention (great guy btw), while he fondly remembers Madworld, he didn't even remember doing the Valkyria games (granted he is very prolific and having done a ton of roles, it's very understandable that he wouldn't remember even if I wasn't asking in great detail). I also met Jessica DiCicco (Leanne from RoF) at the same convention, very nice, remembers Resonance of Fate a bit (I was the second person who brought a copy of the game for her to sign that day) and that she did Rise of Nightmares. I guess it depends on the role and their involvement...Cindy Robinson or Colleen Villard would certainly be interesting as they've done roles in both Sonic and VC, with Colleen also doing Alpha Protocol.
Fun Fact, by random chance, I ran into the VA for NiGHTs and SoA's Fina (Jewels Jaselle/Julissa Aguirre) at another convention. Really cool to hear from her regarding how the recording sessions were for the games.
That being said, I would like to see any of the Binary Domain actors interviewed (including Johnny Young Bosch or Troy Baker) just for any insight on the mocap capture/performance of the game and working with RGG studios (if there was any interaction).