I really don't like this ACT design. The coat of arms is way too complicated.

Other than that though, I love these designs. I think there's something to be said for a unified look to state flags, and Qld, WA, ACT, and NT's two-tone background with a wavy separation is a great feature that could be used for that. Jervis Bay and Tassy have an interesting diagonal wave instead and SA a horizontal one. It then is just NSW and Vic that have rigid straight lines without any of the wave theme.

But even completely unchanged from how this video shows them, I think these are an excellent set of state and territory flags. Way better than the ugly Union Flag w/ Crest designs we mostly currently use.

I just learned that the British colony of Queensland, Australia, adopted the Maltese cross as the state badge and on the flag in 1876 for reasons unknown

Agree with other post re ugly jack. But why does SA have no stars? Better that they all have them or all don't, I vote don't.

I think the QLD and NSW options are actually decent, which is surprising for a modern flag redesign. Not sure about the Victorian one, could do with either making the symbol more regular (i.e. less finger paint style) or deleting the crown (too hard to keep details on) and making the stars loosely drawn too. WA seems a decent idea but could do with a cleaner swan rather than the ruffled feathers on the back. The SA idea looks pretty good but does have hints of invading Poland due to the ~~imperial eagle~~ magpie. Tasmania however is another one I could get behind.

Not a real fan of the current ACT/NT flags and I don't think changing to a wavy line helps them, and the idea for the Jervis Bay territory seems a bit too committee style bland for my liking (like most new flag designs I see mentioned).