Absolutely, in an ideal world aps-c would be sufficient for everyone, ff (which is only defined by the legacy analog film) is mainly a fix for bad iso capability atm, at least unless a high mp camera is here. And ff has disadvantages like the slower x-sync.
But in the real world there are a couple of disadvantages to aps-c: if you use ef lenses you carry and pay for glass you partly don't use, and there are no sealed standard-range lenses for ef-s - Canon nails down aps-c to the amateur or birding sector with these non-offers.
APS-C sensors only came about as a "cheap"-er way to produce sensors even though Canon knew a sensor the size of a 35mm negative was better.
APS-C was a common film size so film users considering a switch to digital would already be aware of the "crop" factor and the smaller "negative" limitations with regards to film grain. Yes, smaller film negatives showed more grain than larger negatives. Sometimes we forget that... Don't believe me? Look at a 4x6 photos from the old "Disc" camera. Best sand painting you will ever see!
Seems to me that production costs for sensors will go down as time continues on, so larger sensors will become more common place over crop sensors. Until then, APS-C will be available and I love my 7D. It is an extremely well thought out camera that is fast and responsive. I love the images I get.
FF has advantages and so does APS-C. Unless one has deep pockets, there will always be budget minded alternitves for the rest of us.