It's finally announced:
I guess the most important upgrades are:
1. HD video capture: this is a very nice news if you wanted a more versatile camera. For those who have a family, and you will immediately agree that it's very important to be able to capture video clips but then it's also hard to bring another DV out.
2. Live view, larger screen and more pixels: but then these were not anything special
It seems like a must that one should upgrade after like two years or even shorter, but as an amateur astronomer, we might have a better upgrade path, for me, I will do like this:
1. Modify my existing camera to enhance its H-alpha performance
2. Buy a new camera
3. Sell the last modified camera