1) Embracing white space is important for a clean and comfortable interface.
Disagree sitting at my desktop trying to process hundreds of emails daily !!!! the different font sizes uneven spcing etc is playing havok with my OCD
2) Many areas of the interface are enlarged for different displays (tablets, mobile, laptops) and to better handle various DPI configurations.
Fair enough why not have different options just like there used to be desktop / mobile version?
3) There are 5 indicators that show on the 3rd line.
Personally I dont care what size the email is its more important to see as many lines as possible
4) 50% of subjects exceed the available space and attempt to show users as much as possible. Your using Test subjects :)
But how much of the line that exceeds the space is actually meaningful or actually required????