Getting elite night credit, arrival points and a small gift was never a benefit when I first purchased my timeshare in 95. That changed a few years ago though I do not remember the year. The elite night credit is a big deal when you factor in ownership, II non Marriott to Marriott and getaways.
Gold and Platinum on the hotel side (free upgrade and breakfast) are the main benefits of the MR program. The number of extra MR points for each dollars spent is a nice extra as is the use of the Visa rewards Card. The 500 points and arrival gift (it use to be one or the other) was never a bid deal.
With the split of MVCI from Hotels, I will be happy if the only change is the arrival gift. They could go back to the timeshare to MR points exchange as the only linkage with no elite night credit.
I do not know how Platinum stacks up to the equivalent in other hotel chains. I know that the MR program in general was and will continue to be devalued over time with the increase in hotel levels. To me, the upgrade and breakfast are nice features of the program (gold and platinum ). Any benefit to timeshare ownership is a gain as long as it adds nights to get someone there.