I'm curious--how did you come to the conclusion that one-half of the rooms are full two-room suites. Of what rooms-- the whole hotel, your floor or what?
I stayed at the Marriott Suk 57 last year during the soft opening when larger rooms and suites for upgrades were still under construction and the Lounge was not open, but returned twice this year. Got a full suite on 39 on my first visit. On second visit I was assigned a room on 39 close by and assumed it was a suite only to find out that it was a standard room. Asked for an upgrade which was granted but on a different floor. If one-half of the rooms are suites I seriously doubt that they would have been unable to find a suite for me (as a PP) prior to registration.
The lounge is differentiated from the Ren by the fact that they have a cook preparing a single different hot dish each day but I think the other offerings are quite limited. IMO overall the lounge is inferior to the Ren, but to each his own.
After about 50 stays I gave up on the JW a couple of years ago for several reasons--but one the primary reasons was the boring repetitious lounge offerings night after night. If it was sliders night you knew exactly what you were going to get--sliders, quesadillas, broccoli w/cheese sauce; same with Chinese night and Japanese night over and over. Maybe they have changed, but it was enough to drive me away.
The option for breakfast buffet in the 57th Street restaurant trumps the Ren's lounge offering.