I think for people who have a lot of additional software packages aside from the standard ones, it might be useful to be able to automize the installation of their additional software after a new install.
So what about a software that works like this:
When you run it, it checks what deb packages are installed, and perhaps what Mintinstall packages are installed, too (for those that aren't debs). It puts a list of all these packages into a file. You can than back that file up somewhere.
If you put this file on another computer on wich you've installed Mint, or on your first computer after a reinstall, and you click on it, the software makes a list of the packages installed on that computer. Then the software compares that list with the list in the file. Then it tells you what packages you would have to install in order to have all the packages that were installed when the file was made. (And perhaps what packages you would have to deinstall in order to restore your old system, too.) It shows you a list that looks like this. Once you've checked the boxes you want to check and unchecked the boxes you want to uncheck, and clicked "Apply", the software would do all the changes (installations and deinstallations) that you've checked.
Perhaps additional functions could be added for the case that a package is replaced with another during a version upgrade. And perhaps the whole thing could be combined with a personal settings backup package, too.