This movie goes downhill after Waltz/Leo die

I agree with this. It actually raised the stakes after Waltz and Cap’s deaths. I wouldn’t say it went downhill, it just switched gears into more of a hostage situation (the wife had technically already been paid for and was free).

I did find the Australian scene bizarre though. As an Australian I like hearing my accent on screen, and can appreciate Tarantino wanting some quirkiness to his cameo, lol. But I can’t imagine there would be any Australians whatsoever in the American Wild West of the 1850s! Zero. Plus Australia was less than 100 years old in the 1850s, and most Aus movies set in this period accurately only have Irish and English accents. This would’ve been too early for an Aussie accent.

Plus Tarantino‘s accent was so bad I actually thought he was playing a South African (eg, the white bearded villain in Black Panther). Oh well whatever, it was funny.

I kinda think that there was a "rhyme" to what QT did with the script structure here, and a certain service to Django as his lead character.

Simply put, when Schultz shoots Candie, and is in turn killed by Butch...the two main white characters are out of the film(with Schultz being dispatched by yet another white character.)

Now, Django is set on course for a final confrontation with Stephen...the black hero will kill the black villain(and, unlike as with Waltz, will not die in the process.) Indeed, before their final fatal confrontation, we get the scene where Django is hanging upside down and Stephen is revealing to him the full evil depravity of his sell-out "house slave" to the white slave masters.

Schulz was Django's mentor for the first 2/3 of the film, teaching him how to shoot, how to be a bounty hunter, how to assert his authority AS a bounty hunter(Django uses Schultz's verbal techniques and wanted posters to convince the Aussie mining men to give him a GUN, for God's sake!), and even how to dress better. With Waltz now dead, Django has to take over the movie and assert himself as the hero -- starting with that big ol' gunbattle that we just KNOW Django has been aching for against all these white bigots. And look how great Django dresses at the end, after that initial silly blue outfit he wears at Big Daddy's ranch.

By the way, in an interview, Will Smith said one reason he turned down Django Unchained is that HE wanted to be the one who killed Calvin Candie, not Schultz. That's movie superstar thinking -- "its all about me." QT protected his structure(the two white men die and set up the confrontation between the two black men) and let Smith walk.

I agree as well, the movie ground to a half when the two main white characters died. IMHO that showed a central weakness in the script and the direction - the white characters were better developed and got more screen time than the black!

Django may have been the title character but it was clear that Tarantino w giving all his love and attention to Waltz and DiCaprio,

Well, they could have been Turkish or from Kazakhstan.
It's just adding to the comedy aspect of the movie.
And Tarantino's accent was not even close. Thought he was a South African.

It wasn't about winning or losing to Shultz. Maybe to a degree, but his impulse to kill Candie was more out of sheer moral frustration than ego. You can see it in his eyes when he shoots the Shariff at the brothel.

He only proved himself capable of getting in good sneak attacks at the right time when the stakes are high. He never proved himself capable of a shoot-out with multiple opponents. In fact, the movie made it clear that he would prefer to talk his way out of one when he's being surrounded.

He only had a one-shooter hidden on him. He didn’t have any more rounds to shoot at anyone else. He was a sitting duck, and knew he would be the moment he decided to kill Candie.

Schultz was trying super hard to get out of there without being forced to shake Candie’s hand. Schultz practically said “I’d rather die than shake this asshole’s hand”. For him, it was a circumstance that was non-negotiable.

I agree. It's a betrayal of his character for him to do what he did. Not that I don't doubt he had a hard time with shaking Candie's hand, but in shooting him instead rather than going ahead with it, he must know he is condemning Django and Hilda to death or slavery again after all the trouble he took in freeing them. It'd be more believable for him to grit his teeth and shake the hand, then try to shoot Candie later on at a more opportune moment. I just don't buy that he would value his integrity by refusing to shake Candie's hand more than the lives of Django and his wife.

It was basically all an excuse so Tarantino could have one of his ultra OTT bloody violent fighting/shoot out scenes that he gets so giddy for. Unfortunately I lose interest by that point onwards.

It would have to be a prequel... :) but I agree. Great character. Kind of like English Bob in Unforgiven.