Gaffer Tape said:
I'll agree with you that in terms of faith, tenets, and objectives, Judaism and Christianity are very different religions. But in terms of history, they are very much the same, as Christianity is simply an offshoot of Judaism, hence the term Judeo-Christian being so popular. The Ark is certainly more religious than the Grail, which is straight-up not Biblical, but they're certainly cut from the same cloth. Add in Nazis, the same characters from Raiders who were passed over in Temple of Doom, and it certainly can feel like a similar movie and probably the overall reason why a lot of people feel that it's a knockoff of Raiders. That's all I'm saying. Again, I feel that Crusade has its own identity, and I certainly agree that the McGuffins are different enough to keep it fresh. I'm just stating why I think people feel they're similar, and I can agree with that viewpoint too, just like I can agree with your viewpoint that Crusade is more invigorating even if I don't necessarily feel that Raiders is boring or lacking.

Historically, Christianity started out as an offshoot of Judaism, but it quite rapidly became something different and its history diverged sharply from Judaism's. The grail legend dates from time when Christianity had developed into something very separate from Judaism and had been very separate for a long time.

I don't see how the ark is cut from the same cloth as the grail. One is a biblical Jewish-origin Middle-Eastern-origin artifact, while the other has its origins in European culture and was possibly inspired by pagan European folklore. They're quite different.

As for Crusade echoing Raiders, I think that was deliberate. They wanted to return to the spirit of Raiders to make up for Temple of Doom. It seems to me Temple of Doom gets criticised for being different from Raiders and Crusade gets criticised for being similar to it.