MC stores user-specific settings. This is usually fine, but it does make it difficult to deploy MC in a multi-user environment, if you want all users to access the same Library with the same settings.
I'd like a Share settings across user accounts option, which when enabled:
* Prompts the user that all current settings will be copied to system-level shared settings. Are you sure (Y/N)?
* Sets a flag in HKLM (on Windows, and in a shared location on OSX/Linux) that tells MC, when loading, to use the settings stored in HKLM instead of HKCU.
* All settings for all users are accessed in HKLM (or, again, a shared ini file on OSX/Linux), with otherwise the identical registry keys and locations.
* If MC's User Accounts setup is enabled, block all users from altering this setting except the Administrator.
* If it is turned back off, set the flag back to 0 (the default) and copy the current HKLM settings back to HKCU (perhaps with another "will copy, ok?" prompt)
This would need to be optional and non-default because, once stored in HKLM, users would have to UAC elevate to write any new settings to HKLM (on Windows). That's actually a benefit for me because I want to prevent users from mucking with the settings once they're set. Linux and OSX likely wouldn't have this issue because the INI could be stored in a shared location where all users have R/W access to it (though if you wanted, you could set up the same security by simply editing the mod permissions on that file).
I have this issue with some of my work deployments. In particular, I use MC on our 84" Perceptive Pixel display, which is in a public conference room. Any Active Directory user can log into this computer and use it without any prep work. And, I use MC in Theater View mode to connect to the VM instance of MC that serves my work-specific Library, so that users can access our library of marketing and lecture videos for things like tours and classes. Unfortunately, it is difficult to get MC set up properly so that it automatically has the right settings when the users log in, because by default they all "start fresh".
Similarly, I can imagine a family with logins for each of the different family members customized for them. I don't do this anymore at home (and we run with a shared login on all of the PCs) and MC is one of the biggest reasons why. I can see in some instances where different users of MC would want their own Library and settings on the same PC. However, probably just as often (or maybe even more often) it would be better for MC to "match" on all users' accounts, because you have a family Library.
Right now, the only way to solve the two issues above is with custom scripting which is difficult to implement reliably. And, if you don't have a Windows Domain and your users run as limited users rather than admin users, it is essentially impossible to solve (because the limited users can't import a REG file without elevating). I can actually solve my work problem, somewhat, with Group Policy on our AD domain (which can import a REG file), but it doesn't always happen reliably immediately at login, and often doesn't take effect until the second login, which makes it tough to use. All of that is, of course, way above the capabilities of the average home user.
So, an option in MC to cover these cases would be good.