Hi,
Regarding the control panel issue, it sounds like you had customized the file "cpanel" via the menu Display->Views. Remove the customization and it shold display the control panel view which has been completely rewritten for 1.6.0
The width can now be controlled globally via the Files tab of the configuration.
The images on the product page have always been centered inside the left area. So it must be something that you had customized previously.
Regarding the hikashop_checkout_address_left_part and other classes of that view, there was some mistakes. That should not have changed. We've published a new build which fixes that. You can download it again on our website if you want to have the correct classes back.
The price of shipping charges needs to be entered manually when you want to change the shipping method of an order yes.