This VQmod extension removes all unnecessary fields from product form and leaves default values.
You can easily modify (delete) operations to un-remove desired field.
Removed fields are: Location (index 15), Minimum Quantity (19), Requires Shipping (22), Date Available (24), Dimensions (25), Length Class (26), Weight (27) and Weight Class (28)

Should work on OpenCart versions 2.0.x - 2.1.x.

Keep in mind that this extension might not work properly if you are using another extension that puts new rows
into product form, such as adding "Price without tax" row etc.