Yes, why, not how.
Now we see how Tantiss came to be as it was, or at least the closest we've ever seen. And having it as a training/growing facility for elite troops during the rise of the Empire is makes more since than having it be isolated and forgotten by everyone but Palp and Thrawn for years on end.
This isn't polishing a turd, this is Filoni and Fav trying to set things up to effectively erase the sequel trilogy using the 'World Between Worlds' from Rebels to show how alt timelines can exist in Star Wars.
Fact is it sounds like their is a plan for an live-action Ahsoka trilogy in the future, the Rogue Squadron movie, and bunches of shows.
Filoni and Fav are going to try to reconcile the old EU with the new Canon, and so far they aren't doing a bad job of it. Trying to keep them old EU and the new canon completely separate is pointless, and only give KK what she wanted. What Filoni and Fav are doing is effectively undoing and rewriting canon to erase those horrible films.