Off topic - I decided to weigh-in when I constantly see it mentioned - as from my experience of real use, your comment will cause mis-lead of some understanding of e-ink screen.

I assume your "vast majority of application" are the applications built for capacitive touch screens, not for keyboard quipped devices that mainly using keyboard to input, like traditional PC, Symbian non touch phones etc.?

If you mean the modern touch screen apps, the answer is close to impossible. For the current e-ink touch screen, the frame rate and responsive time is much much slower than any of the touch screens, far behind. It will be difficult even to perform basic functions, like scroll, zoom picture etc. Not saying it's impossible, but it won't give the same user experience as you expect as a touch screen.

This is the main reason e-ink as a secondary screen, or even as a primary screen, does not give a great user experience on mobile phones. Because customers "expect" the same experience as touch screen, or thought they are the same, but in fact they are not.

As far as I know the industry have not solved this problem yet. I don't want to go to far but I am happy to discuss if interested. However the main reason I decided to write this reply is that you seemed not used this before, your statement is based on IMAGINATION.

And I really think those are the reasons some people will get frustrated.

Like you mentioned anything above 5" you regard as "big" and could not put in pocket. I am not sure how you define your 5" screen, will it be a 18:9 (in fact that will probably be the size of 4.5" in your experience), a 16:9, or a 4:3? Will it be bezel-less 18:9, 16:9 or 4:3? They can vast a lot on actual size. And clearly you don't seem to really giving a clear definition, because if there is a 5" with 18:9 screen I don't think it won't fit in your pocket. I remember you are still using the Jolla 1, a 5" 18:9 will very very likely being physically smaller.

I want to make it clear that I am not asking you to back up our project nor buy the product, but wanted to state again that you need to try it before conducting any conclusion - statement like 5" being too big, or AMOLED being over saturated are the same as "Chinese (or insert a nation) food is awful" because they do have different variation.

And remember, even the definition of "pocket" can vary because I have no issues fitting a 18:9 6" product in any of my trousers, and it seem to be the case for our team members. It might be a little bit special on yours?