Galaxy S4 restarting and freezing after root
FWIW I've been having a similar problem, but without the modifications you mention. My process was to root, install SuperSU, Titanium Backup and then restore a bunch of apps.

The first time I got the problem, I thought I had restored some system apps or something, so I reverted to stock, and tried again, but being more careful to only restore apps and stuff like wifi access points. This suffered the same problem (but possibly less so).

I've gone back to stock again, and I'm going to try it to see whether I get similar behaviour without rooting. If all is well for a day or so, then I'll root, and see if anything changes. If it's still stable, I'll start using apps that utilise root and see what happens.