The current attribute inspector dijit does not validate fields in a meaningful way. For example, if a feature service does not allow null values for a field it will not force the user to input a value because the "" != null. So effectively the field is left blank. It shouldn't be that hard to do validation since dojo provides validation via https://dojotoolkit.org/documentation/tutorials/1.10/validation/ or by wrapping a validationtextbox in a form widget. For me to code this up on my own requires me to write a completely custom attribute inspector which seems silly. Validation options could include valid email address, numbers, dates, etc.