I really hate when this happens, I'll try another revision. This is why I hate reporting issues, perhaps I'll refrain from reporting another issue again, since all I do is end up wasting everyone's time. Other games work fine, so it's not my hardware.
Edit: Tried an old revision, 4.0-6734 and the characters appear just fine. Care to explain that? No settings were changed during either test, 4.0-8445 had the invisible models, yet 4.0-6734 has them show up. That's a mystery! How can an old revision of the same ISO, with the same settings work fine, but newer revisions royally screw up? No settings were changes, no drivers were changed, and yet, this happens. I bet anything the newer 8xxx builds are getting more accurate and hate the video card that I have. Has to be.
The whole "it must be your end" ploy is the very reason I never want to report Dolphin issues again. The fact that they can't be reproduced is also very disheartening and frankly, almost causes me to be disenfranchised because reporting these issues is just simply a waste of my time, it solves nothing, it helps no one and it sure as hell doesn't do any of the Dolphin programmer any help, so why should I bother?
I give up, 100% give up, refuse to make more bug reports, trouble tickets, etc, there is no point.
Edit 2: Also, tested 4.0-8103, characters are normal there, so something clearly broke between 8103 and 8445
Edit 3: Tested working perfectly in 4.0-8301 and in 4.0-8350, 8360, 8370, and 8381
Tested many more revisions, the issue I noted went as far back as 4.0-8390, tested 4.0-8385 and the issue was nonexistent. Revision 4.0-8388
https://github.com/dolphin-emu/dolphin/pull/3315 ShaderGen: Toggle Value of uninitialized color. This revision here is the very revision where I noticed the issue began, anything before 8388, the game was working great and I seem to be the "only" one to have this issue. Which makes no sense.
To sum up:
4.0-8385: Issue does not exist, solid models
4.0-8388: Pull request 3315 seems to be the culprit in making the invisible models. No other games that I have show this issue, clearly this broke THPS3 for some users, I more than meet the system requirements and no changes to the settings were made
Not that this'll do me any good because no one's going to believe my report anyway.