What does everyone think Indiana Jones 4 SHOULD have been about?

I loved the movie too it was great, but I wished that they had actually made a movie like 3 years after crusade came out, but instead they just made a comic book about it. It's called "Indiana Jones and the Spear of Destiny" and it is about the spear that killed Jesus and the legend is that whoever poseses the spear will take over the world, but if they were to lose the spear, they would die.The movie would be set in the year that Hitler died but months before the event occured and in fact, that was the only religious artifact the Nazi got their hands on in real life but then it was recovered by American agents and then the next day, Hitler suicided. Indy's dad also goes with him on this adventure.