QUOTE
just wanted to know why it worked for some people
Impossible to tell without knowing exactly what OS, hardware, etc. they had when they did it. Moving plists out of their normal position is a fairly routine to force an app to re-create the default settings. The biggest problem is that the steps usually say to "trash" the old plist. That is over-kill and will then require more work to re-set all the changes you had made, assuming you remember what they were!
However,
replacing plists, especially ones from different OS versions,
is something entirely different. It may have been done successfully but I have never, until now, heard of it and certainly never seen it suggested as any kind of fix for a problem. And in this instance it is not even a 'problem,' it's simply an attempt to get something back into the OS that Apple itself removed. Things change. Sometimes we lose things we like. Usually we get new things. Move on and learn the new features.
Just because you can do something doesn't mean you should. - Anonymous but famous last words
OTOH, if you really like something, build your own computer! Some people still do that!
Or try using Linux, it's very open to individualization!
The only way I'd try this is via multiple clones - try it on one of them and boot to that. But I suspect that it won't work, simply because there is a boatload of stuff in that first Framework file - including a ScreenSaverEngine.app which is version 5.0 and dated August, 2013, and several .plist files which look like they may be pointing to new versions of things in Mavericks.
Really not worth the messing around, if you ask me. Of course, I don't use a screen saver, and haven't done for the better part of the last decade, as they're really not necessary. They were invented to prevent phosphor burn-in for old CRTs (plasma screens are also susceptible) - with LCDs this is no longer an issue. Even with newer CRTs it had ceased to be much of an issue. My Macs all have screens set to go to sleep after about 15 minutes of inactivity. Now, screensavers are mostly used for entertainment value, as you've been doing with the mosaic option. There are various others that will display a variety of iPhoto photos in different ways. Not the mosaic you're used to, but perhaps a reasonable substitute.
