Mara's death, while the scene itself was bad, does make some sense. You have to realize that Jacen was trying to turn Ben to the Darkside. What better way than to kill his mother? It just so happens that Karen Traviss killed her off. KT hated Mara Jade, and Jedi as a wwhole. She didn't listen to the other authors.
Being a huge Mara Jade fan, I would hate it if they brought her back to life at this point. I would like to see her death scene re-written to give her a better, more fitting death. But since she is dead, and I hate saying this, she should remain dead. Bringing her back wpuld be a huge undertaking. How would it even be done? Luke would not want her to be cloned, so that would eliminate that idea.
KT may hate Jedi (why the hell did they ever let her write anything but those Republic Commando books? it boggles the mind), but I recall in some interview they did with her that said she actually really liked Mara (presumably moreso before she became a Jedi), and had a hard time writing the scene. And even though it may have made sense, the fact of the matter is likely that had she not taken unilateral action in not checking with Zahn (which any author with any sense would do), it would not have been approved.
And I don't think anything should be retroactively changed, but I'm sure they could magic up some kind of explanation for a resurrection - they have brought people back from basically force-ghost-status before, just not very much lately. Cloning is right out, but I'm sure there could be some sort of way to do it that isn't totally stupid.
And hey, it's only been a handful of years. SW has done weirder things than let presumably-dead characters come back in that span of time.