- Hard eject with soft disable (e.g. like CD-R/RW drives which physically lock closed while burning). Ensure that it unlocks when the power goes off!

You do realise that the optical drive eject buttons nowadays are soft eject, and therefore largely useless when the power is off, and the mac floppies have had the paperclip emergency eject, like optical drives you're so enamoured of, since pre-PowerPC days, right?

Could you imagine a sport where people run around shooting each other with balls propelled by compressed nerve-gas?

I can see an xkcd strip of it already.

Android actually indeed, from the ground up, allows applications to advertise to the system that they are willing and able to handle and display certain forms of data, or publish that they will allow the user to do certain things. When an application makes a request to have a certain data-type handled (like "open this web page"), the OS selects which of the installed apps that can will get to handle the request.

But this need not create a lot of complexity. The failure you are describing is a usability failure of cruft upon cruft of setting and defaults that were not properly constrained by good UI guidelines of where they should be found and how they should be set. Right now setting the default browser on most desktop OSes is a snap: just run the browser and it will ask "Do you want me to be the default?" and we're done. I think that if the OS has a good system for managing these settings -- and WinMo does not because it never cared -- this need not be such a nightmare.

What it will be nighmare for, though, is tech support "Wait, you have what dialer installed? You browser is which?" Still, there is so much power in having a controlled and OS-blessed way to chain little programs together, each adding their own value, from different creative individuals. Very UNIXy.