@mmustac - i'm glad that you found the feedback useful! :)

@dvratil - Thanks for pointing out the View->Message List-> Theme option, I didn't know that such an option existed, and agree it shouldn't be lost. I wonder therefore, if it's rather about trying to help make these options more user-accessible. Ie end-user education related, coupled with more clarity at the UI end?

could we perhaps have both showing at the proposed location? i.e. size, reading time (e.g. 35Kb, 1mins to read)

do you think it's worth adding the dates to the weekly calendar, or would it look too busy?

Looks great! I especially love the time to read, and also the html/plain-text identifier! :)