Well simply solution is to try a GH2 if you feel the ergonomics don't work for you.
Both are very good cameras, and both have their fans.
I personally hated the G3's feel in hand, but the images and everything else was very nice.
I don't do movies or anything so spending $300 extra for a GH2 maybe is a little silly, as a $599 G3 takes images just as nice as $899 GH2, but I'd rather have spent more money on a camera want to use rather than $600 on one thats going to just sit and gather dust because it feels uncomfortable in my hand.
The lack of grip just didn't work for me. I know I'm in the minority and many don't have a problem with it, but I also know I'm not the only one.
Simple solution is to get your hands on a GH2 or even an older G series and see if you find it that much better.
If you do, well, then either pay the extra money or see if you can live with the G3
No choice is right or wrong, but knowing is rather priceless.
Maybe you will find the Gh2 is not any better for you and you can happily go back to the G3 (or somethign else all together)
As it sounds now, your probably just going to always be wondering if you should of got something else and that can certainly eat at you, taking the fun away from shooting because all your going to be thinking about is the ergonomics over and over.
Been there, done that.
Knowing is half the battle