On Windows XP I could edit or change a file name from the open/save dialogue box. There are times when I need to fix a typo or rename a file or give it a number so that it doesn't conflict with a file I'm going to save. This is very convenient and I hope Apple adopts this for OS X.
As for the Command key vs. the Control key I much prefer the Command key because it's more natural. With your thumb on the command key, acting as the axis, you have a better rotation or twist of your wrist as you type the other keys with your other fingers. The control key would make the other keys further away if you use your thumb on it, therefore, making you use your pinky finger. This sometimes forces you to use your thumb to press a key. It was a little problem at first when I first started using PCs along with Macs but you get accustom to it and it becomes easier to remember to use control key for windows and command key for macs.
What OS X Could Learn From Windows