I am completely against this. I like the walled garden. Occasionally there's something I'd like to do but can't but that's rare and (despite some notable exception cases) I prefer the safeguards of app store only. If Apple has to build a process to load apps untethered I would expect that to be exploited for malware.
You know, just because you want the protection of the walled garden doesn't mean you have to subject everyone else to your restrictions. There no reason there couldn't be a preference that allow apps to be loaded easily from other sources, or restricted to just the Apple App Store. Apple could even have this preference turned on by default, but still have it available for users to turn off if they want. Then, the only way to get infected by these malicious third-party apps would be to if you actively decided to turn off this protection. You, personally, could just not do this on your own iPhone.
Oh, wait. That's exactly how this is handled on Android.

So the reason people are getting hit on Android is 1) the apps on the Google Play store are not vetted as well as Apple's iOS App Store (possibly true), or 2) Android handset owners are turning off this restriction -- in other words, it's their own fault, and not due to some extra protection Apple's App Store would have given them. All automobiles have seat belts now, but you can't blame the car manufacturer if people don't use them.