If you close the last window of a program, I can see where someone can argue there is no need for the program to still be open.
I just wish they'd make up their mind. Some Apple programs, and some few of the programs I use often [like Moho] quit when I close the last open window. I got used to the Apple way when I switched, and I can live with it. I just don't like it when some apps, esp. Apple's, are inconsistent with this.
About more buttons: I like the current arrangement well enough, and I wouldn't like anything that wasn't symmetrical, because I'm left-handed and I'm ambidextrous where the trackpad's concerned.
I hate the mighty mouse buttons. When I'm going to use the MBP for a long session, I plug in an old 4-button MS optical mouse, and all is well.