Rebuilding forums into an app would be a terrible waste of time, as they have the mobile version of the forums, which is platform independent and is made to simulate the look and feel of a native app, anyway.
A mobile shoutbox app would certainly be interesting, but it would function very similarly to the current mobile browser shoutbox. You can probably just put an icon on your home screen to a bookmark if you want that convenience.
As far as staying up-to-date on news, there's a reason they added RSS feeds to their news feeds. Monster Paradise RSS Feed
. These can be fed into any number of RSS readers.
If you were looking for something like an app that gave you a notification when a new announcement post was put up on the forums, there's something that would either involve resource-intensive forum scraping, or something to be built by Aeria (which also provides no return on investment).
If the interest in this is high enough, I can make any of these, but it would only be for Android (as I do not feel like paying for an iOS dev license). If you're interested, let me know (via PM or something)