He really hasn't aged well, and if they are going to keep pushing a big demon archetype, giving him some love to make him an exciting option for Renolock decks while also letting reno warlock compete with the other two reno classes will be a fantastic and cool way to do so. Here's my suggestion, thoughts?
I always liked the card even if it was the worst of the highlander cards. I crafted it long ago just so I could play a weird midrange-ish version of Renolock. There is just something so satisfying about summoning a giant board of demons with that awesome animation ( Same reason I like Bloodreaver Gul'dan haha )
To make it not a demon is kind of weird though. It obviously is some kind of Voidlord which is definitely a demon in both HS and wow lore. Maybe just costing 8 and having taunt is buff enough for it to be good. Even if you get it from Skull of the Man'ari/Voidcaller you wouldn't be too sad cheating out a 7/9 taunt demon.
Renolock hasn't been good for a long time now in wild so this certainly wouldn't make it op.
Are there any instances of them actually buffing cards? Not just to previous levels, but past original levels?
Unleash the Hounds when the card was reworked it got reworked to what it does now but for 4 mana, then it got buffed to 2 mana, then blizzard realized 2 mana UTH was broken so they settled it in for 3 mana.
Edit: originally Unleash the hounds was a 1 mana card that gave +1attack and charge to all your friendly beasts.
This is unnecessary in my opinion. He was designed as a late game board swing that cheats a lot of mana. The problem is: Warlock already has much more efficient ways to cheat demons. Voidcaller and Skull of the Man'ari are two of the strongest mana cheat engines in the game. Even at 8 mana he is way too slow compared to those two cards and making him better when they pull him is a buff to them and they definitely don't need any extra help. He would surely see play if those two cards didn't exist. There's no reason to buff a card that's already powerful just because it is overshadowed by other totally overpowered cards.
Dumbest thing ive seen a while. Buff a card with Nzoth like effect. If you think it should be demon, you must want this summoned by voidcaller the weapon. 5000 thumbs down. Reno kabal classes are braindead easy to get advantage over opponent already.