According to ComicBook.com on Aug. 24, Ian McDiarmid spoke at Fan Expo Canada in regards to rumors about him returning as the Emperor in "Star Wars Episode VII". Apparently, the main rumors were of him returning as a force ghost or an end result to cloning technology.
He didn't seem completely adverse to the possibility of the return and denied having signed any deals. McDiarmid did mention there would be new villains.
“Well, there’s so many rumors. I like you, know nothing, because there are no facts yet. We know that John Williams is doing the music. Kathleen Kennedy announced that when we were all in Essen, but she and everyone else is unable to say anything else at the moment, because I understand they’re still working on the script".
McDiarmid has heard of all the ghosts and clone possibilities, but still mentions that there had been no talks or deals that have been set. Basically, until he is contacted about anything regarding "Star Wars Episode VII", he acknowledges the fact that he currently feels he's not in it. He did acknowledge the idea that there's a whole new world to address with this next sequel that he won't be working towards it and cherishes the idea that Disney will be addressing the old school nature from the previous films and incorporating that into the current ones.
"There might be some old favorites in it, but I should imagine it’s about the adventures of the descendants of the first characters and new villains that no one except George has ever imagined. And I hope it is, because the great thing about Disney is that it will continue in a new form with new people and be reinvented, just like all great works of art are sooner of later".