Why would have Rick Riordan selected Apollo to be the god who gets punished?

Question

In Greek mythology we have bundle of gods who are rash and careless with their behaviour, including Zeus himself. Except Hestia, I believe, none is impeccable. Then why Rick would have selected Apollo? What trait he had that made him apt for the role where the god acknowledges his mistakes and works to improve?

Why not Ares or Hermes? They too, once somewhere in the novel appears to be thoughtful and humble of their mistakes, for instance, when Hermes laments how Luke had turned out.

What made Apollo standout for the series?

Answer 1

Rick Riordan answered this question in an interview:

Why did you choose to base the series on Apollo rather than any other god in the pantheon?

Apollo actually gave me the idea, since in the original myths he was twice sent down to Earth as a mortal by his father Zeus. I decided that if it could happen twice, there was a precedent. Why not send him down to earth one more time? (Apollo still has not forgiven me for that).