@Silverblade:
I would be among the first to ask Araki for more relevant Caesar participation in the human-pillarmen affairs, but at the bare minimum being the emotional anchor of the second part is much more "plot relevant" than anything Lisa Lisa or Stroheim had to say for themselves. Joseph could have used that andidote though. But them the hotblooded shonen fightan rules.
I don't mean to say that Caesar being an emotional anchor wasn't effective at all. The JoBromance was definitely there in spades. And I'm sure that Lisa Lisa gets complaints about not contributing to the plot as much as she should have. But at the very least, they can't be removed from the plot and still have it function. Meanwhile with Caesar, it totally can. Don't get me wrong, Caesar being there is definitely much better than never existing, and he is still one of the series most beloved characters in the grand scheme of looking at every main cast member of all eight parts. But like you even admitted, there could be relevant Caesar participation.
I didn't mean to give off the impression that Caesar was a bad or absolutely worthless character. Emotional significance is indeed a major part of properly engrossing readers and conveying storytelling quality. He just unfortunately lacks any integral plot structure merit. That's pretty much a fact. At least Stroheim can take credit for awakening Santana and getting the Pillar Men's existence known, as well as getting Kars to evolve into his perfect form accidentally. Araki accomplished more with Stroheim's mistakes than he did with Caesar's entire existence.
And then you lost me. Part three is a mess when it comes to handling its cast. Only Polnareff and maybe Joseph had decent parts to play. Jotaro hogs screentime like he is young Joseph and that for 15 volumes instead of 5. Kakyoin and Iggy skip a good stretch of the story only to pull a glorified Caesar. And Avdol? Say something, Avdol!
I didn't mean to say the character spotlight in Part 3 was perfect by ANY means. Like you claimed to be the first to ask for more relevant Caesar participation, I would ask for the same on behalf of Kakyoin, Avdol, Iggy, and even Joseph. I know I could care less about that last minute half-assed backstory Kakyoin got after hitting the water tower due to his lack of presence and bland personality besides priceless meme moments. I'm just saying that if he could have all six main characters at least do one or two memorable things that makes their presence in the plot relevant (such as defeating one-time enemies, figuring out the secret to Dio's stand (and Vanilla Ice's because without pre-existing knowledge, he's guaranteed to kill at least one person), and leaving Vanilla Ice open), and yet can't even have Caesar do ONE thing in Part 2's plot that makes his presence integral, then something obviously went wrong.
This is not a contest to see if Caesar is better or worse than other characters. We're just evaluating how expendable he is when it comes to the sequence of plot events as a significant flaw in and of itself.