First of all, and that one's more easy to see, there's a line in the application template that ask for applicants to explain why their character would be a good addition to the game! It's detailed further there, and keep in mind this isn't a mandatory addition to applications, if you can't think of anything to say there's no need. But we do encourage people to at least give it a thought and consider the kind of CR or developments they could play out, when intending to bring someone over.
Second, the re-app template has an addition that is mandatory: we ask for three ideas for things the character could do upon their return. This doesn't mean it'll be monitored and, should the ideas fail, the character will not be forcibly dropped or anything. It's merely a guideline, of course, a little on the same line as the addition explained above.
If you have any questions or doubts regarding these, let us know!