I think bitcointalk.org is the absolute worst place to talk about Bitcoin, except for all the other places.
There's something about this place that keeps it relevant in spite of its warts, and I'm not sure that whatever it is would move to a new forum. It's been tried before.
The thing you are looking for is "the network effect". This community thrives because this is where the people are. I tried to use some other forums in the past, but since there were few other users it quickly devolved into interesting links back to this forum.
I am not sure having a standalone application is the best way to go. I find it convenient that I can log into the forum from any computer. Having to install software is a big turn-off for many of the less-technically inclined.