Have people been saying that?? With the grain being a fixed part of the actual screen, it's not really going to look different in any other installed OS. And what has the display of text in Windows vs OSX have to do with anything? O_o
The font antialiasing (font smoothing) comes down to how it's implemented in the operating system, it's software based and not related in any way to lcd grain issues.
About the RAM and resolution, that really confused me, what exactly are you saying? Are you complaining that the resolution size, or/and the quality of colours when viewing movies???
Here's my reply from my understanding of what you said; the amount of memory your video card has doesn't mean you'll have different resolutions. Yeah the video card does play a part in how the rest of the display hardware will work, but the display panel itself will also have limitations.
As far as I know most other laptop manufacturers are making machines with 15" screens, that support upto 1280x800 resolution. If you want 1440x900 you get a 17" PC laptop. But yes I know, Dell (and others?) have reduced the pixel size on their higher end screens to squeeze in more resolution on screens.
Personally IMHO, things are already getting to be small on the 15" MBP, I don't want to have to squint at even higher resolutions. I take your point though, that you want more options.