IMHO, you should know what the current models are capable of by renting one or both and trying them out. You can take this to the bank, but Canon will always be producing new cameras with new features to stay competitive with company 'X'. Hopefully each new series will be better than the previous. If nothing else, technology loses value in 12 months anyway. But I always have a camera with me for that 'shot' that didn't get away.
For me personally, I'm ready to sell my 7D in preparation of what lies ahead for the 7D2. I've got a 5D3 and 1D4 that covers all I need (or want) at the moment. Selling my 1D4 is next in line.
Best of luck.