And here is JI claiming that Richard II would be filming after TH's three movies after Coriolanus. We are now some way beyond that juncture, and it hasn't happened. I guess one of two things: there was no actual commitment, or there was an agreement to do it but some problem with funding meaning it has been kicked into the long grass: http://hiddleslokid.tumblr.com/post/96863166310/tom-hiddleston-in-talks-about-the-role-in-next