They had to be conservative in terms of budget on raiders. Once the movie was sucessful they were able to do some of the more wild and crazy ideas in the next picture temple of doom.

Lucas would challenge himself and spielberg to top their previous sucessful films. And each indy film had to be bigger than the last and top it in terms of action and effects. Lucas gave himself the same challenge on the prequels to top the original trilogy or at least return of the jedi. We all know how that turned out.

They did in some ways top Last Crusade with Crystal Skull. Still i liked crusade and hated skull.

Well i don't entirely hate skull lol. Kingdom of the crystal skull had some moments i enjoyed. But the slapstick was overdone imho. Which i think Lucas started to do over the top slapstick sequences in return of the jedi. Topping it all off with the dreadful phantom menace and jar jar and the gungans.

Some of the more jokey slapstick type things in doom and crusade i enjoyed as a kid but they annoy me to no end as an adult. I appreciate Raiders far more because it treats the material seriously. While the next films tried to make a fun rollercoaster ride. Once the material is treated in camp and self mockery it no longer works.

I think Marquand himself said when directing jedi that he wanted to treat the material seriously and not campy like they did on the 1980 flash gordon. Too bad Lucas still was allowed to put sillyness into the film. I wish marquand stuck to his guns of playing the material straight forward and without self derision.