I would really like the emails that I send to my Evernote account to be able to define NEW tags. I often find notes that I have emailed in that have #<tag name> in the title, since the tag name wasn't defined. I would highly recommend that this wouldn't be a separate command to define new tags. Often I don't remember exactly which tags are defined.
As a PhD student, Latex support in Evernote would make it a fully capable lab research notebook for me, whereas now I only use it for simple web clipping. I really hope the evernote team takes a serious look at this