This has gotten me thinking about iOS and if it needs to be put on a diet. And while it might be merely overweight and not obese I think that yes there's some trimming that could be done.
First there's those skeuro tricks like the moving shadows in buttons, reflections etc. Those would require code and as they serve no real purpose why not remove them and take off an easy 'ounce' or two.
But the real bloat, to me, is the built in apps. In particular things like Compass, Weather, Stocks. These were good, even great, when iOS first started and the App Store was a pipe dream, but now they just aren't required anymore. There are dozens of alternatives, many free and many better, in the App Store. If Apple is truly enamored of their versions then keep them, as free downloads in the App Store, but take them out of the base system and their 'fat' with them.
Another way to handle bloat would be to remove content like keyboards, Siri voices etc until we need them. It would be child's play I would think to download the files during the initial setup since the device has to be online. And a little instruction note could explain that initial items can be downloaded and where to find it in the settings.
And in how about some better handling of 'hidden' bloaters like cookies, cache files etc. Safari's reading list is a prime example. Give us a way to limit how much storage space it can use with an alert to clear some of it out. Better ways to mass delete emails, messages,photos as well.