Many threads in this forum are about problems/lack of features/bugs about formatting and some answers justify that stating that Evernote should stay lightweight and simple.
But formatting is (in my opinion) the main feature over just opening plain .txt files in an advanced editor. Both options allow you to:
search text in all notes
keep note creation and last modification datetime
use URLs as hyperlinks
quick usage / lightweight application
And .txt is a more universal and standard storage format for your notes... you could even recover part of the text from a faulty hard drive.
So Evernote developers: take this into account, I think it would be really frustrating to lose users against plain old text editors