It's really hard to say....APS-C market is getting smaller and smaller due to huge pressures from mirrorless cameras. Canon is trying to catch up with EOS M.
I honestly think mirrorless (NEX, XE-1) is equal if not better than APS-C.
Also the fact that ff is getting cheaper and cheaper meaning people will either go small and compact (which btw gives the same IQ as APS-C, better AF, higher burst and more) or Full frame.
Canon isn't commited to EF-S...just look at the HUGE selection of EF-S lenses (NOT!)