We need corrective actions to prevent the next Lion Air similar accident. Criminal prosecution of these pilots provides nothing more than the satisfaction of extraordinary punishment for poor CRM.
Some of us are looking for a heavier hand to be laid on Lion Air by their regulator to minimize the occurences of crew errors.
I would look to the adequacy of training as well as the failure rate culling process of those who do not display expected CRM abilities under pressure. Standing down a few pilots before an accident might be in the right direction.
I don't know what problems exist with the regulatory body so no comment there as yet. I typically don't look to them as causing an accident other than permitting the situation that contributes to an accident.