After lurking FT for years, I finally registered just to comment on this post. While I'm not platinum elite like many here, I am gold elite, and spend lots of my time in marriott branded hotels.
Marriott Rewards base points system isn't that great in my opinion, but the promotions are what have kept me loyal for years. As a supplement, the promotions make up for what the base points system lacks. However, the promotions continue to be not as common, and continue to decline in value.
The days of promotions at all times--when one ended, another began were great. Also, the free certs for category 4/5 hotels after 2 paid stays is much more desirable than "2500 points after 2 stays." What does 2500 points get me? 8 hours in a category 1 hotel?
I just started using starwood recently due to their points system being a bit more friendly. Also, Wyndham just changed their points system, all hotels are 15k points a night! One hotel I stayed in Boston earlier in the year was 40k points that I had saved for YEARS with wyndham (because I've been loyal to Marriott, only staying with others when I HAD to), and it is now 15k points.
What I'm getting at Marriott, is that... we do have options... and your promotions/points systems continues to decline.