Already added a couple of written opinions from my cellphone before, and they went off without a hitch.
However, the use of an app is not for fixing browser bugs, but rather to sell features and to spread the word (and to make $'s too, obviously).
My suggestion is, finish the page, then start writing different, not-very-important things you'd want to do with an OpiWiki app. As they grow bigger, delete the redundant ones, or pull apart the ones that are too hard to do, or too important (because of many counter-intuitive reasons, the most common-sense-y of them being that, if it's so important, why do you want to make it app only?) and once (if?) you have around 20, give the app serious thought. Hire people, make money through the app to pay them, etc.