Personally I would love a movie or mini-series - which leans heavily on the more graphic, grounded aspects of the EU - beginning with the Malachor V incident, showcasing the backstory and rise of both Darth Sion and Darth Nihilus - ultimately being found by Darth Traya and forming the Sith Triumvirate. I'd love an open-ending that shows Sion taking the Republic Vessel and arriving at Peragus, and a post-credits scene of Nihilus sending Visas Marr to hunt Meetra Surik.
I'd also love to see a series with Gungi set 100yrs or so after the OT in which he'd be restoring or expanding a new Galactic Jedi Order as a threat from the Void begins to destabilize the galaxy. Ideally he'd have the wisdom of Yoda (if not more) but without Yoda's arrogance, given his coming-of-age during the CW and the GCW
I wouldn't trust Disney to do it well, honestly, especially with how they've rolled with Lucas' idea that SW is for kids and dialed it up to 11. Let a lesser-known studio create it but with Disney money, and we might have a decent set of KOTOR films / series