Root Root access On/Off functionality

@scary alien Thanks. I assumed that it may not that easy as flipping a switch but then I am a user, not a developer, may not know everything. That said, I think there is something like this in CM, if I am right.

@Jfalls63 Thank you for the warning. I have thought it through for a while and although I admit that I am scared of messing up with the phone or data steal by a malicious app, a few things I really would like to have. For e.g.
- there are many legit apps but their permissions are hard for me to digest, or lets say I don't use those features of the apps. I would like to control these permissions. This is biggest pet peeve of mine for some of the apps but haven't found alternative apps that do exactly that or that well.
- I would like to have a firewall. I am just too used to firewall on PC and not having it on android gives me a little uncomfortable feel, esp when odd websites open up. Although android firewall doesn't look as straight-forward, would like to learn something new
- Thirdly, I want to block all ads if possible. I am among the cord cutters so YouTube is almost our sole mode of TV entertainment. In that case, ads really drive me mad, although 15 seconds, I still don't want it.
- Then comes ext SD card writing access. I have tried a lot to get this sh!t worked out without rooting but failed so far. Whats the point of SD card if I can't write on it in android system? Supposedly, google sorted this out in Lollipop but can't figure out on my phone (5.0.1).
- Titanium Backup. Just had a hard disk crash but glad had a backup. Would like to keep phone backed up too. Sometimes I do keep data on the phone that isn't backed up anywhere else to work on the go.
- Finally, update if its worth getting. Galaxy S4 is the only phone in that range that hasn't gotten 5.1.1 yet. Not that I will use almost all features but if there is a feature that I would like to have, would prefer to have it via some ROM. I still haven't gotten stagefright (or whatever that is, MMS hack) patch!!.
And so on, so forth...

Again, thanks for the warning.