Really? 🙁 An 11" MBA can completely replace your iPad with very little sacrifice in mobility. And most likely increase your writing productivity. Try that scenario in reverse.
I have tried that scenario in reverse. Although, I can not say that I write exclusively with my ipad. I almost never use my mac book pro out of necessity, I only use it for writing, if I am there using it for something else ( i.e. warcraft, or photoshop, which still require a computer for the most part).
I can not speak for everyone, but I am not limited in writing by my ipad and a BT keyboard. I type at about 60 WPM on both. I have found no sacrifice in writing on an ipad with a blue tooth keyboard, nor have I felt limited, or otherwise had to sacrifice writing productivity to write on an ipad.
It has a trackpad and palm rest. Have you seriously used a keyboard with an iPad for any length of time? How's that arm doing? This is a good read on
Gorilla Arm and why the writer ditched the iPad and went back to a mac.
I have seriously used a BT keyboard with my ipad for a serious length of time, and found no pain or discomfort in doing so. Not sure what was wrong with the writer of the article you referenced, maybe he was holding it wrong.
It seems strange to me when people tell me that I should've gotten a mac book air, instead of an ipad. With an Ipad I have the best of both worlds. I can use the ipad without keyboard, and when a Keyboard is needed, I take it out and use it. I am not limited by the ipad. Perhaps compared to a Macbook Air, it is underpowered, but I am not finding any difficulty in using it, or finding any limitations with it, because, as you say, it is underpowered comparatively. I find the papers that I have written on the ipad compare favorably with the papers that I previously wrote on my mac book pro.
Not really sure what you have against the idea of people using the ipad, as they want. The only limitations I have found with the ipad, is the fact that Blizzard, has not stepped up and ported a Warcraft version for the ipad.