I'm probably in the minority here. But I would be totally into a reboot of Indiana Jones. Indy was a my childhood hero, that series and I have a lot of fond memories, dressing up at Halloween and stuff like that. Let's face it Harrison Ford is what 70 now? While he IS Indiana Jones, let's just accept that he is too old to carry the torch any longer and just close that chapter, go back and start all over again.
Disney now owns the rights so it's probable that they'll want to go there at some point anyway. I say go for it, let's just bite the bullet and hit the reboot on that one, rather than do injustice to the series by dragging out a 5th movie.