Personally I would really love to see one new dark side user who we have not seen before.Of course many say, including me that she would be an iteration of Darth Talon, but Darth Talon was nothing else than a 'sexy' sith with absolutely no background. In contrast, Devon's character and journey has so many things to unpack in the future. She is talented, fascinating and most importantly we rarely got the chance to see one jedi apprentice fall to the dark side like this. Troughout the show they measured her perfectly. Devon's story has layers we understand why she lost it in the end and we can relate to that. She has come to the realisation that the dogmatic ways of the Jedi don't work anymore.
I really hope that the creaters will not give her a redemption arc, we have seen that countless times. Please BE DARK just for once. I would love to see how she develops into a very formidable dark side user alongside Maul. I would love to see how Maul trains her, what methods he uses, what lightsaber techniques he teaches, I want to see that on screen. And last but not least I view this as a way to honor Lucas's vision for the main antagonists in the sequels. To keep things simple, I am in love with this idea of Maul taking an apprentice who by 'sheer coincidence' is almost identical to the main idea of George Lucas for Talon, but with actual background.
I have seen a lot of people obsessed with the fight between Maul and Vader, I was far more focused on Devon, simply becuase of the fact that altough I loved Maul vs Vader, I literelly dropped my jaw when I saw him appearing from the fog but we know their story from the front to the back nod. Dave Filoni finally goes back to the roots and treat Star Wars for what it is. The Inquisitors were awesome, Maul's story was beyond amazing, the final battle could not have been better, now the only unfinished story remains which is to mold Devon into a proficient and terrifying dark side user with great detail troughout it's progress. But I fully trust Filoni he is a true successor to Lucas so cannot wait for season 2!