For advocating the purchase of ad-free apps, you guys should really buy Titanium. Those screenshots are a couple years out of date, and a legally acquired copy would be updated, and would have been a year or so ago when they changed the design. I kind of miss the old way, but the new design has a lot to offer, too.
As for ad blocking, Google no longer allows ad blocking apps in the Play Store. Ad blocking itself doesn't require root; what requires root is changing the HOSTS file, which is full file system access. HOSTS ad blocking is far from ideal and many apps just use the IP address of their ads, bypassing HOSTS, and thus pushing ads to users who explicitly don't want them. And while blocking ads without paying for a 99¢ ad-free version, pushing ads to a user who has gone to great lengths to opt out is a little worse. Of course they could simply not use the app, but some apps don't have an ad-free version, or it's not reasonably priced.
Not all devices require root to use USB OTG. The Galaxy S3 is one of them. USB drives typically show up in \mnt\usbdisk0, and that doesn't require root access, as long as you have a file manager that can browse to that location. I use ES File Explorer (supports root for mounting \system as r/w, but needs it for nothing else) and it can. In fact you can often browse to \ and \system without root access, you just can't change anything. So you can look but not touch.
Android has taught me a lot about Linux, which was previously a mystery when I'd experiment with Ubuntu or Mint, or Fedora/Red Hat. Now I feel more at home in those systems... too bad I still need Windows for my gaming.