That said, some PAINFULLY obvious things which would be hugely benficial for adoption;
- LaTex support built in
- Markdown (either in every note, or allowing you to add 'markdown' boxes, if just for writing code)
And a stretch goal;
- Better PDF/attachment integration. In a perfect world there would be a Dropbox extension which creates an "Evernote" folder in your Dropbox and any attachments are automatically stored in a notebook-hierarchy file-system within that folder. This would autoupdate to reflect what's going on in Evernote.