I agree. Not sure what my card of choice will be after August, but it won't be my SPG Amex. I will be very interested to see what others are suggesting.
Also, I haven't seen much discussion about availability under the new program. My experience has been that SPG availability is very good while Marriott availability is very poor. Given that, I may just shift my spend to a cash back card like Chase Sapphire Reserve that effectively gives me 1.5% back.