The first and third suggestions are definitely interesting ideas. However, allowing users to download older TUs comes in handy when playing syslink games where using the same version as other users is required. Not to mention the rare occasion when a newer TU ADDS bugs to a game. Sometimes you just wanna have the ability to go back a version. You always have the option to remove TUs that you do not wish to keep.
Great start to suggestions for F3, and hopefully you've started a trend for other users to contribute their ideas as well! I know I have a few of my own.