Originally Posted by phltraveler

Couple factors here.

1. Marriott didn't want to tick off the old Lifetime Plats (750 nights/2.0M points) by taking their grandfathered level and not grandfathering at the highest possible level. Technically the creation of new PP with ambassador created a new discrete rank but one that offered little benefit (Your24, 75% pts bonus for PP over 100% for PP w/ Amb, the Ambassador). Making it with PP w/ Amb made it sound like it was just PP w/ an Ambassador with no clear benefits (the majority of the MR platinum pool had never had an ambassador pre-merger, there were limited trials).
2. Marriott also saw how the SPG LTPs (500 nights + 10 years at plat) were also outraged by the fact that they would be grandfathered below. They addressed the point of 750 Nights + 10 years pre-merger to give SPG Elites a bite of the new LTPP apple, and then point #1 applies for the SPG Elites that qualified for new LTPP to make LTPP w/ Amb seem minor in difference.
3. Lightspeed PMS connected to Starwood Reservations computers couldn't properly reflect status above Platinum to the front desk clerk. There were other ways to get at this information, but this depended on the hotel management to go out of their way to do it and then convey that information to staff, versus it just popping up when an FDC interacted with a guest (checkin or otherwise). Now all of the Starwood properties (according to the timeline previously published) have been switched to MARSHA backened/Opera PMS, which properly reflects statuses above Platinum.
4. Hotels had enough going on with benefits changes (Platinum breakfast benefit at more properties, late checkout being guaranteed and time changes for different elite pools, etc.) and the differences in hard benefits promised at property being virtually non-existent at ranks above Platinum that MR decided to just do one set of changes first, let properties adjust, then take care of it in the rebrand.

MR now gets to divorce itself of the legacy names (Rewards for Marriott and Preferred Guest for Starwood) and any previous gripes/complaints about the integration.

As information is given now (e.g. no mention of any elite benefits at Plat in below), elites at Platinum and below have no reason to complain (no reduction in benefits or increase in benefits for higher ranks).
Elites at Plat Premier or Plat Premier with Ambassador will be happy, because after being greeted as just merely Platinum at properties for months, it will be more likely that properties will properly recognize status for upgrades and other aspects of on property experience.

Rebrand occurs, celebration, properties roll out new materials, people learn their new metal (or rank in the case of Ambassador) and the properties learn the difference, time passes...

I have no crystal ball, but in addition to making the different ranks clearer with the change to Titanium and Ambassador names, it sets the precedent in the future (six months? A year from now? Longer?) to carve out future benefits changes, particularly for the 100 night + $20K eligible spend guests. 100 EQN + $20K is no longer the 75 night rank + ambassador in name, but one that has an entirely different name...