That design is...awful. Tons of wasted space, prominent screen real estate given to interactions the user will never engage and less than 50% of the screen is given to the content I am there to see?
So what I heard is that people would just prefer something like the Thunderbird, basic but functional - https://addons.cdn.mozilla.net/user-media/previews/full/152/... and you don't care if it's ugly. However, You can't just think like gmail are only used by engineers who designed it. Most of the users are not.
> one doesn't know what he should look at first.
Pot, meet kettle.