Most chains do this annually - it's not a shock. We're in a strong hotel market right now: occupancy is up, rates are up. Hotel points and categories are strongly correlated to avg. room revenues - all of the "lurkers" here on FT over the years have confirmed this.
Two reasons I don't think we're in a "devaluation" state:
(1) If you do a lot of business stays, you're earning a lot more points thanks to the higher rates. I know I am in 2006 vs. two or three years ago. Our negotiated rates at big-city Marriott are up close to $200/nt., whereas finding $150-160/nt. was easy in 2003-2004.
(2) With the new credit card, the base earning rate - if Marriott Points are what you seek - is 17 per dollar, up from 15 per dollar with the old card. So even if you are primary acquiring points from leisure stays, the couple of extra points per dollar takes at least a little bit of the sting out of your favorite property jumping up a level. Under the old system, I was actually opting for 12 MR points + 1 Starpoint per dollar

, except when we were in the Visa 2x promo.
So yeah, Category Creep sucks, but I don't think the sky is falling.