So technically, even prior to the new program, the RC's were supposed to offer "as available" upgrades to Platinum's. It used to be (up until late 2017) that they only rooms they wouldn't upgrade you to were Club Rooms and Suites. Earlier this year, without any public announcement that I am aware of), they started only excluding Club Rooms (meaning you could now theoretically get an upgrade to a suite). So as I understand it, in the new program, the upgrade policy will be the same, ie only on "as available" basis and excluding Club level.

I will say that in my experience, with is mostly US RC's, they were very stingy with upgrades so I am skeptical that things will change with the new program. In general, SPG Elites as St Regis's seems to have much better upgrade hit rates than Marriott Elites as RCs.

I think the only increased upgrade related benefit from the new program at RC with be the ability to use the Suite Night Awards at a Ritz although I can't find any explicit confirmation that Suite Night Awards with be available at RC's and from reading what the SPG elites on FT say those awards are pretty hard to use as is.