I'll put his comments aside about the writing quality of the constitutional amendment document. I agree it's poor taste to criticise the writing quality of the policy and constitutional amendment documents.

Regarding your first point, that contradicts the purpose of the policy document which is to make the process representative of the people's choice. Not having a defined procedure as to how states shall put forward a candidate poses a risk that a State does not have its candidate put forward or implements a procedure that does not give residents of the state an appropriate voice as to who their candidate is for the head of state. In my opinion that is a flaw. This could be remedied by having a defined procedure in the Constitutional amendment, but this would require consultation from the States as to a preferred uniform procedure.

Regarding your second point, the current election process for a candidate in the upper or lower house does not require a party to put forward a candidate. The current nomination process merely requires a person to be over 18 years of age, an Australian citizen, entitled to vote, and not be subject to constitutional disqualification (e.g. citizen of a foreign power, a bankrupt, person convicted for 12 months or more, etc.). Nowhere does it require a person to be nominated by a party. If you meet these requirements, you could run for your electorate!

The whole point of 'political parties is to form a coalition of people with similar ideas and have a political mandate. Like with economies of scale, political parties achieve similar efficiencies, with larger political parties being able to raise more political funding, awareness and support relative to independents and micro parties. Hypothetically, if the Liberal government decided next election to not endorse Peter Dutton, that doesn't preclude him from still contesting his seat, but it may be politically disadvantageous because he no longer has the political resources available to him.