Iizuka does, however, comment on the forthcoming 2015 Sonic game, as translated by My Nintendo News:
Nothing new, other than the fact that we will get more news this year (as opposed to having to wait for Sonic Boom to be released).“At the moment, the core Sonic team at SEGA is working on a new title that will use the traditional look and mechanics of the series, which will get more details later during the year.”
“At the same time, Big Red Button, an entirely new studio, is working on a new version of the entire game universe, called Sonic Boom, which will use an entirely new aesthetic and is designed to accompany the delivery of a new range of toys and a new cartoon series.”