I live on my computer, or in my computer, or with my computer…well, anyway:
How about this:
Font Control (independently size, type and color, any and all letters, words, sentences, paragraphs).
Editor (changes on the fly).
Line and Character Counter (on input).
Sample types of Poetry (click to see in a user sizable preview pane)
Save As (option for writer to “save as” to local machine as DOC, PDF, etc…).