Primarily, I’m hoping for this feature for threaded emails, since when looking through a stack of threaded emails (especially ones that turn into hierarchical branches because of tiny changes in the recipient list or subject) it’s very annoying to click through to even look at email.
Basically, what I’m hoping for is a similar concept to what Eudora does for email. Selecting multiple folders (or, at least, email threads) causes them to have their contents all show up in the contents pane in the three-pane view. (In other words, say I have three threaded conversations on email—I select them and all of the threads’ contents show up to be clicked in the pane)
It’d make it a lot easier to navigate and look through emails, and probably other folder contents as well.
Also, still crossing my fingers for email metadata as sorting columns soon. I’d love to just leap into archiving email into DevonThink, but the lack of ability to see easily what date the emails came from (and inability to precisely filter it) takes away some of utility of the function.