I do not believe that just changing screen can mess so much, otherwise they designed OS wrong, that you need to rewrite a lot of stuff if you change screen(size or resolution). Let's say you do not reinstall OS if you change monitor of your desktop. I do understand that some changes have to be done, but as they want to provide OS to other companies - adaptation should be easy one and screen is not so vital part.

I do not care with delay, as delay can happen and at least they told it ahead, as everyone knew it would happen anyway, the problem is that they do not tell what is the real reason of delay and what exact HW changes were made and even why(no need for details, as it can be not only related tothem), but telling "all you need to know..." and saying non tech details without specs like color-something different(do not remember wording) is not exactly fair move to people who bought product.
Let's think what will happen with any seller on ebay or kickstarter who would delay and send at the end different devices, while he knows it already, but still did not updated you with info.