/home is doing the function of that don't touch and save for another install
if you want another partition for backup purposes, i would have it, but on another hard disk, you already have enough partitions to handle there
have another partition on the hard disk just makes things complicated and less secure, is the same as put all your eggs in one basket
when you plan to reinstall everything, just don't delete /home, leave it unformatted and remember to make backups if that partition is accidentally formatted during the new install
format the wrong partition is so easy...
"Is it generally safe to repartition or is it risky?"
in general, if you don't have much experience, is easy to destroy everything