A reboot of Indiana Jones wouldn't be the end of the world. Star Trek was rebooted and remove the angle that still had Nimoy involved but the filmmakers were asking people to accept Chris Pine as James T. Kirk, a role that was made into a Pop Culture Icon by William Shatner. Literally its the same field as Indy, it wasn't a literary character or a Bondesque move where they interchanged and this generation was able to accept different actors in the same role, Shatner up until this year WAS Kirk, it was understood and with syndication new audiences were introduced to their adventures on a daily basis. I'm not a huge fan of the original Star Trek but you don't have to be to understand that with the TOS crew they ran that into the ground with the last few adventures being liked by diehard fans but overall admittingly the weakest of the bunch. Same happened with the TNG crew.
Rebooting is severely risky but if done in the right hands, you get what you got with Star Trek 2009, a new audience anxious for more that likes the cast and the feel of the original characters without direct copy or direct mimicry and a Core audience who is willing to go on this adventure but still has their fond memories intact.
A new Indy wouldn't negate Ford as Indy. A new actor wouldn't have to look or copy Ford's performance, Pine certainly didn't channel Shatner but gave a similar feel. It would also keep the established Ford performances in a sort of Holy place without any further missteps or crumbling storylines. I didn't hate KOTCS but it certainly didn't peg the ol' Indy magic for me by any means and I wouldn't even say that I liked it. I was kind of indifferent about it. I would much rather see a new Indiana Jones done well given the same treatment as Abrams did with Star Trek and have a concurrent adventure that could still capture the magic but keep the old in line and respectable.
Diehards will never say they like Pine over Shatner or Quinto over Nimoy they'll say they are acceptable replacements and they like them in their own way but still treasure, respect and love the originals. No reason Indy couldn't share the same fate.