If you like butler style service and an historical property, as it sounds like you do, then you should really be looking at the St. Regis. With Virtuoso confirmed upgrades up to Astor suite guaranteed if available at the time of booking, it really is a no-brainer choice.
R-C Central Park is nice, and a great choice for park views, but as you do not value club level (one of R-C's strong points), I would think StR with confirmed upgrade would be ideal.
I would rather eat my own head than stay at the Plaza...