The only complaint (and it is a large one) I have is that Indy 4 seems to be more of a George Lucas movie (over-reliance on special effects, forced/shallow dialogue, etc.) than a true Spielberg film. The first three Indy flicks have a true balance between Steven's craft for film-making and George's stunts and effects. Both are great storytellers in their own right, but they need to weave their strengths together to find balance when collaborating.
I am, however, a huge fan of fun, silly, suspend your disbelief while parking your car movies, and this is one of them. Fun has always been the key word with Indiana Jones, and so it remains.