Not exactly your argument, but I much prefer the App Store to something like Google's Play Store. App Store, even though it has its issues, is a lot better simply because there is more oversight. There have been numerous cases where malware has gotten into Play Store apps, and only taken down once someone tells Google, instead of Google actually doing their due diligence as arbiters of the Play Store and verify each app before allowing it to publish. Apple does actually verify each app, and consequences aside this means I don't really have to worry about malware issues.

It would be nice if I could install something on my own, e.g. side-load an app, but I haven't come across an app that I've seemingly needed that for. I think the fact that you can only go through the App Store also keeps things consistent for the consumer, so they don't wonder why they sometimes have to install it using iTunes, sometimes through the App Store. Of course there's also the economics of Apple's 30% cut of App Store app purchases.