At least four further changes are necessary to bring about appropriate reform of the Senate.
First, elections for the Senate and House of Representatives should be required to be held simultaneously. There is no justification for separate elections for the two houses - and indeed the enormous cost of doing so means that, in practice, the ballots are usually now held together.
Second, the budget bills must be seen as a special case. These need to be enacted with greater urgency and certainty than other bills and cannot be delayed for months lest the government run out of money and face dismissal. No matter which party is in government, it ought to be able to enact its budget without having to go to an election. In this case, the Howard proposal has merit. Budget bills ought to be able to be enacted at a joint sitting after being twice rejected by the Senate.
Third, there should be fixed terms for both houses. While the term should be set at four years, it may be sensible to give a government some leeway, such as the capacity to call an election up to six months before the set date. This would reduce the power of governments to manipulate the electoral cycle to their advantage, including using it to threaten the Senate with an early election.
Fourth, all senators should serve four-year terms and not, as is currently the case, double the length of the members of the lower house. Eight years is too long for any parliamentarian to go without seeking re-election. This change would mean having to choose all senators at each election, rather than only half. It would give some advantage to the minor parties because they would need to get fewer votes to achieve a quota for the election of a senator.
I'd add the Australian Democrat proposal for proportional representation in the House, parliamentary consent to treaties and military action. Really, the prime minister of Australia is probably the most autocratic office in the democratic world.
Our prime minister can make war at will, can sign and ratify treaties at will, can name judges without legislative confirmation, controls the career path of every senior public servant, has absolute control of the House of Representatives which can be dissolved at will, has no bill of rights to contend with, and has the right not to be told anything by the intelligence agencies.