Server Side Validation in Camunda

I’ve run into the problem of doing server side validation (checking if a file exists).
The main problem is that so far we’ve avoided having to add any self made rest services at all and we are now somewhat reluctant to add the dependencies just for that.

So I thought it would be neat if Camunda could support Server Side Validation like this;

 MyTaskListener
  complete() 
  {
     throw new ValidationException(JSON payload);
  }

where most notably ValidationExceptions don’t generate log entries/stack traces

and on the embeddedForms side:
camForm.on('server-validation-failure', function(payload) {...

Basically it would work in parallel to the existing event exception handling mechanism with a customizable payload and a more “silent” default.

So before I make a feature request. What do you think, bad design?