Below is an article yesterday in a Silicon Valley newspaper about credit card rewards regressing- http://www.mercurynews.com/nationworld/ci_11541727
Roughly 40 to 4% of credit cards have reward programs compared to 20 to 25% of debit cards having them. Frankly I am surprised that their are that many debit cards with rewards because I do not know of many banks at all which offer points or cashback on debit card purchases.
Taking away rewards is not a wise move. The rewards are the sole reason I put all purchases on credit cards. If you are not carrying a balance you have no incentive to pay with credit cards if you are not being rewarded for doing so.