What sort of performance do you expect from a 70d? It seems you expect it to be a marked improvement vs an incremental upgrade. I wouldn't hold my breath.
Canon has always stayed with their original premise, deliver a good camera for the best possible price. This means that they carefully do a value engineering on features versus their cost. I've watched people pickup cameras in Buest Buy, they listen to the salesmans spiel, they buy the cheapest one.
The Nikon D7001 might be a slightly better camera, but the D70 will sell more due to the lower price. Canon's expertise is high volume production at low prices, and they do not want to lose that edge.
I think they learned with the 5D MK III and will go back to their roots.