A distinction should be drawn, I think, between constitutional considerations and political considerations. Some of the matters you outlined could perhaps be speaking to political considerations, but as a matter of constitutional compliance it was thought prudent to ensure that the Prime Minister not be obliged to hold the consultation nor be obliged to appoint names submitted to him as a result of the consultation. Otherwise, it could be seen as fettering the prerogative of the Prime Minister to recommend according to the dispositions or constitutional conventions set out as matters of convention and the powers for summoning persons to the Senate set out in the Constitution.
The bill is currently drafted in such a way as to ensure that the prerogative of the Prime Minister and the powers of the Governor General are not in any way fettered. Matters of political practice may develop, but the bill cannot and does not speak to that.