김희주  I totally understand what you are saying.  but there are some problems with what you are suggesting.
  1.  The maps here, all call it the Sea of Japan.
  2.  "The East Sea" has its own complications.  to whom is it eaat of?  korea?  china?  .  Most assuredly Europe.    The term has its own negative connotations in western culture. Nearly as bad as "The Oriental Sea"  or some such garbage.