I hate to be a naysayer but I'm not sure how helpful this would be to your average poet. Things like rhyme and meter counts are rarely involved in early drafts of poems. If you're shooting for a certain style or form typically you keep that in mind as you produce but I'd wager the vast majority of work being produced today doesn't follow any major scheme.
This seems like a tool made for poets without the input of poets based on a skewed idea of what a poet needs.
EDIT: I've been writing poetry for about 4 years and have taken 5+ university poetry classes. I'm by no means a "poet" or in anyway an expert on poetry but to me, I'm not sure I understand the strength in this.
First, when I'm looking for something to write in I absolutely want a minimalist interface. Anything more than that is an immediate distraction. I use iA Writer on a Macbook Air or on an iPad. I've heard combinations like this described as "typewriter" like in their single-task orientation.
This app has too many distractions. While writing the last thing I would want to break my flow is a barrage of information about bits and pieces of my work that, for the most part, aren't relevant. I do not write with any sort of meter or rhyme in mind (rhyming as a crutch is an amateur device and the biggest red flag of someone with an incomplete knowledge of poetry) but after critiques from peers and layers of revisions sometimes these elements do come out and get accentuated in my work.
In the ballpark of features I would like? Collaboration! Workshopping poems is by far the most satisfying and useful way to improve your poetry. Find ways to share documents with multiple people, get feedback and respond to it. Things like Google Docs/Drive have barriers of entry that if you can remove would make this app excellent for sharing with peers who aren't local.
Right now I use a combination of Google Drive, iCloud and email to share my work, keep track of revisions and send out requests. Its probably the most major hurdle in my workflow and something begging to be addressed for writers.
> Find ways to share documents with multiple people, get feedback and respond to it. Things like Google Docs/Drive have barriers of entry that if you can remove would make this app excellent for sharing with peers who aren't local.
This idea was an actual project I started building at one time, but from all the people I know it didn't seem to solve their problems. Unaware of the potential user base I left it stagnant for a long time. Maybe knowing that indeed there are others with the same idea, I should hop back on that and do a MVP to test it out.
About this tool as a helper, it is adequate in fact to the term IDE. For all you say in your comment about concentrating on the subject first, is the same mentally I shift to when coding by using vim, instead of an IDE (which I use mostly at work only).