I agree mostly with the idea, but I'd make a couple notable changes.
First off, he needs some sort of mental domination ability. During his time as Sith Emperor, he dominated the minds of multiple powerful force users and turned them into his servants. He was much more known for that sort of force power as opposed to lightning which was always more Palpatine's thing.
Secondly, I'd make him specifically Valkorian and create a Zakuulan tag, then switch all his Sith synergies to Zakuulan ones. There are a ton of other Sith lords in the old canon to boost the Sith roster, so he's not really needed there if they start adding more old canon stuff. Also, Zakuul has a bunch of other things that could be added as characters for the tag (it was made in an MMO, so there's lots of enemy types from Zakuul). The Knights, Archons, Skytroopers, Arcann, Thexan, Vaylin, etc.
The one thing I'm not sure about for a Zakuulan tag would be how it would be received by the player-base. I'd imagine there'd be a fair bit of 'who's that' going on, but I also think there's a lot of opportunity there to create a fair few interesting characters.
