Marco,
As Eduardo said, I also believe that is not possible through customizing.
In my view, if you set up any field as mandatory for tcode MI01 through customizing, you'll impact the Sessions (MI31, MI32, MI33, ...), due to the fact that all of them use MI01 to process the batch input session.
One example is that the field ISEG-GRUND is not avaliable in the MI01.
You should try even SHD0.
Regards,
Fabio