I plan to replace my GH1 with a G5 or GH3, most llkely the G5. I expect a significant improvement in print quality, though not huge, as well as better high ISO performance.
For you, why not wait if you are undecided and not in a hurry? A few months from now you will have more information and may even see a price drop.
"We paint with our brain, not with our hands" -- Michelangelo
Portrait, figure and fantasy photography at Silver Mirage Gallery: