I've been using TB since it was first released many, many moons ago! Here is just a couple of thoughts on the new UI.
The Density settings seem very arbitrary. How about leaving the Default setting and adding Increase and Decrease Density buttons, similar to the Fonts Menu, to change the Density in 1 or 2 pixel increments or 1/2 of a line space at a time.
Put the Menu Bar back at the very top of the screen. Silly, confusing move!
Get rid of the big blue dots for the message counts, the number itself was just fine and not as distracting.
Thank you for giving us the choice of Table View or Card View. Card View is nearly unusable. This is one reason why I don't use Gmail unless I absolutely have to.
Other than these, you have done a good job. I use TB because I can't stand Outlook and don't want to use a Web Mail account ( I have at least 4 of those! ). Quit trying to be Outlook or Gmail and just be TB. The people who use TB like it the way it is ( or was! ).
