Actually that was the Tantive III, a CR70 corvette. The Tantive IV was a CR90. /nerd
I agree that the Jango/Boba Fett angle stretched things a bit, but as things turned out, without it we likely wouldn't have Ashoka, or Rex, or Anakin's valuable character development in the Clone Wars series.
Jabba made sense to me, it was Tatooine. I think his usage could have been done better though. Chewie was a bit pointless, but harmless enough.
The sequels were garbage. Good actors doing the best they could but the didn't even get the chance to all work together until the final film. Wasted opportunities, wasted potential. The humour should be the cherry on top, not the thing trying to hold the characters together.
Neither of the droids needed to be in it, and their presence undermined and contradicted the OT. As did Chewbacca's, because how would Han not believe in the Force if his best friend literally fought alongside Yoda? And we didn't need Boba/Jango Fett to have Rex, Ahsoka and the rest. The clones could've been clones of anyone.
You talk about humour not being enough to hold the characters together, but in the prequels they didn't even have that. None of the relationships felt genuine, the dialogue was at best stilted and lifeless, at worse utterly cringeworthy.
Honestly, just watch TPM and compare it to TFA, just observe the difference in how the characters interact with each other, the dialogue, the humour. It's just much more genuine and relatable in TFA, the characters are more likeable and seem more like actual people. The lightsaber duel in TPM is technically brilliant, but devoid of any meaning - it just kind of happens because the bad guy turns up and so the good guys have to fight him. There's no story reason for it, no connection between the characters, we don't know anything about Maul other than he looks cool, why should we care who wins? Whereas we know who Kylo is and then he kills Han Solo, so the audience has a reason to hate him and Rey has a reason to fight him.
The sequels had plenty of flaws - the lack of an overall story was a huge mistake and TROS was a mess which undermined the previous two films, but in almost every category, as individual films, they were better (well, at least the first two).