On one hand, users are told that they should never ever, ever install applications from untrusted sources. They should always use the play store because applications are scanned for vulnerabilities and whatnot.
On the other hand, we have people telling us that one of the great advantages of Android is that you can sideload apps - bypassing the store security model completely.
On one hand, a VPN needs root access for transparent proxying (or at least TOR does). Changing the hosts file needs root access. Changing gps.conf requires root. Lots of useful operations need root access, so if you are concerned about privacy and security, or just want more control, you probably want root.
On the other hand, root is stupidly hard to obtain, and users are strongly discouraged from doing it anyway because it opens all sorts of attack vectors. Unless the manufacturer provides a legitimate method to do it, the operation of obtaining root itself, like on iOS, often relies on an unpatched local privilege escalation vulnerability. Note that any application can exploit this, not just the rooting app.
I don't support Apple's walled garden approach, but we can't argue that they have a much clearer picture with regards to security, and the results speak for themselves. Malware in the Apple devices is rare, whereas in Android it is rapidly becoming routine. Unfortunately, you sacrifice flexibility for enhanced security.