The font looks not comfortable and the page looks very crowded/
First off, Thanks for taking time to provide some feedback and for trying the new Outlook on the web experience!
I just wanted to let you know that you are able to disable two options that I think might address some of your feedback.
Click on the gear in the top right, and then disable the Sender Photos and Attachment Previews.
This will help reduce some of the colors, and reduce some of the preview pictures that are shown.
Hope this helps!