As implementers will never have to revisit them again once they support such a block completely, it aids their work by limiting the effects of additional character to fewer blocks.
For that reason alone, and for no other, it might be worthwhile to ask WG2 to move that character and close the 0300 block.
Don't worry. We will have no trouble filling the empty space in due course. -- Michael Everson * * Everson Typography * * http://www.evertype.com