I really hadn't thought about "Rich and Happy" as an "I Want" song - more of a "I got all this and I'm convincing myself it's what I wanted" song; I really like the counterpoint between it and "Our Time" - they have a sort of symmetrical place in the show's structure with the overtly hollow and cynical sentiments in "Rich and Happy" contrasting with the touchingly naive and idealistic sentiments in "Our Time". The problem with the show is (as much as I love it) is the contrast is totally on the nose and lacking finesse, largely due to the heavy-handed cynicism and disdain for the characters that "Rich and Happy" displayed - it made Frank and the world too unlikable at the start - thus the change to "That Frank". I think you're right about "Like it Was" as an "I Want" for Mary - but to go one step further and say that each of the main trio gets an "I want" song and "Franklin Shepard Inc." can be seen as an "I Want" for Charley ("And you know what? I want it back.").