One of the developers closer the ipod classic could probably give your more details about what "partial" means here, but as far as I am concerned battery charging works perfectly on my players (ipod classic 80g and 120g). There are still things to be fixed with the USB, but nothing that makes the rockoboxed classics unusable.
To my knowledge, except for the HDD interface there is basically no difference between the 80/120g models and the 2007 (thick)160g you have, so this means you shouldn't have any issues with the battery charging either.
The port is not 100% functional, the players crash every now and then but overall they are usable and I am very happy about running rockbox on them. I recommend that you give it a try and see for yourself if rockbox is what you want or not.
PS. Welcome to rockbox!