I am glad you are not crazy!
Almas Mahfooz has shown me it is possible to dynamically change the required property in Dexterity.
By "not natively", I'm eluding to the fact it would be possible to use Sanscript through continuum to do this, but strictly speaking this is not a MS supported thing to do.
This post shows you the principle..
www.timwappat.info/.../How-to-make-GP-company-login-text-boxes-longer
Tim