About the "marked new games as always shown", I'm the one who added it because it bothered me to always had to disable the favorite mode to find the game I just added (and, if I added it, it usually means I want to play it), to place a star on it (if I added it, and want to play it, I would certainly like it to be in the favorite list), and to put back the favorite mode.
Having the new games shown is easier to place a star after adding the game to the HDD.
I don't think seeing a little "new" icon or a new game is very polluting your display for one day (24h), unless you add 50 games per day to not play any of them :/
I did it thinking about the gamers, not the ISO collectors. just disable the "mark new games" option in the GUI settings.
The favorite is not the best way to make different list for different users.
The best way is to use the categories, create a category per users, and only display your own category, or the parental control.