Random Rant: Australian Constitution

I recently read a copy of the Australian Constitution, which I should have probably done a while ago, seeing as I'm an Aussie. My opinion of it: It sucks. Not entirely, but plenty of stuff should be scrapped, and some stuff should be added.

Here's my proposed changes
-Make the Executive branch headed by a DIRECTLY elected President. The prime minister, for one thing, should not cater to the cares of his district above the cares of the nation. On the other hand, the President should sit in parliament and be directly answerable.
-Guarantee humans some basic rights: The right to free speech, religon, food, etc... Does not go far enough
-The Budget should be voted upon by the people. This idea I got from zompist.com. See his argument for better reasons why than I could give you.