(This may also apply to Android Tablets or any mobile device that is designed to be viewed preferably in landscape)

Portrait Mode for Clips is not a suitable way to enjoy a clip on an iPad. A device like this has plentiful real estate horizontally and clips should reasonably be viewed like on PC: in Landscape Mode with no cropping, trimming or alternative placement. Clips in Portrait Mode sacrifice clip clarity, either by cropping parts of the stream or making it smaller than it reasonably should for viewing. These are reasonable sacrifices on a portrait-preferred device like a phone, but for an iPad, this leaves immense amounts of wasted space which can be used.

What works (or works better) for the majority of mobile devices doesn't mean it works for all of them, and the mindset shouldn't be that way.