Your comments

According to this document https://technet.microsoft.com/pl-pl/library/ms174393.aspx QUOTED_IDENTIFIER is enabled by default. Please check if you didn't changed sth by an accident. We would like to stick to the "default" behaviour and don't put the "set quoted_identifier on" statement into generated script.

Let's us know what did you found.
Yes. You're right. I've added your idea to our todo list.
AFAIK MS SQL Server supports both way of quoting names. We're using quotes (""). This is the facto standard among other database engines. Maybe there is a difference between "" and [] that we don't know.
You can export models as a old user and import them as a new user. This is a temporary workaround.

PayPerUse purchase for existing users is on the QA stage right now. It will available in two weeks.
Hi,

Fixed. The fix will be available for you in the next production update (next week).