Yeah I thought that rumor sounded kinda fishy, but I wanted to be sure.Most of the complaints I've seen on 4Kids dubs over the years have been pretty valid. There are some nitpicks for sure, but generally speaking, I think people being upset over how they handled their dubs is pretty understandable. Even their text edits were pretty inconsistent. I wasn't referring to just the Japanese text, but any sign of Japanese culture like how they handled rice balls or made it so that Yu-Gi-Oh! DM was set in America instead of Japan.
Well you did bring up 5D's, so it wasn't quite clear to me if you were focused on just one series or all of the Yu-Gi-Oh! 4Kids dubs.
Whatever you heard about Judai's voice actor was a baseless rumor. There isn't any evidence to suggest that he demanded a raise and not getting one lead to GX's shorter fourth season. I remember hearing about an interview with Chronos/Chrowler's voice actor where he said that Konami basically had Synchro monsters ready to go, so they cut GX's last season short.
They weren't really any darker than what they already covered in the Dark Signer arc, so I doubt that was an issue, especially when they would have just down them down considerably like always anyway. The 5D's dub ending felt more like a sudden stop than an ending to me, but I'd still give them credit for at least attempting to give fans some kind of closure with that ending.
Eric Stuart explained 4Kids reasoning regarding the whole rice balls thing(Even though I thought it was silly as well):rice balls