Launcher Command-line Options
Until the release of the new 1.6.x launcher, I was able to use command-line options to allow me to create desktop shortcuts to allow my children to connect to my own (in-house) Minecraft servers with very little fuss. They each have their own account and neither of them were ever required to type their own (strong) password or remember a server IP.
This was thanks to the fact that the launcher supported an almost mind-numbingly simple way to create a shortcut and create icons on my children's computers:
{path}minecraft.exe -u=<username> -p=<password> <server:port>
I was also able to use similar shortcuts to quickly log in as them on the server to assist with game-play issues, probably needless to say, this was very handy.
While the addition of profiles is a general plus for many users, the removal of command-line parameters has proven to be very frustrating in my situation. This new launcher is, IMO, not particularly user-friendly and is generally confusing to my children.
I know I'm not the only person to use the command-line options, and I would like to see this very useful functionality return in some form.