There are a number of different places where reputation is displayed. I understand the need to be more concise in the app with its smaller screen, but currently it's shortened everywhere. It should be taken on a case by case basis. My thoughts:
Post "signature" -
I think this one should stay truncated. Depending on the number of badges and the timestamp, a larger display may be dangerous
I've given this one more thought. The only situation where it doesn't fit, is when there are literally thousands of badges. Nobody has that many badges between 1k and 10k, so I can't think why it should be different from the website
Sidebar (exclusive to iOS app) - Absolutely not. It's so cramped already. There are some pretty long site names. Also, the value there is cached, so could be far out of date.
Profile page - This is where I'd like to see not just a longer amount (10k vs 1k), but rather show the full reputation (10432). As it is, there's no way to see true reputation, and I think that's valuable. Especially for self-navel-gazing. I think it's important to be able to see that information somewhere
Anywhere else I'm missing?