The question is does the trait even trigger in all slots like Maw, or is it restricted to first slot only?
I mean, he actually doesn’t look that bad. Not amazing in all situations, but not unusable. 32 mana can still be easily obtained using “Unity Mana”, a kill with probably an extra turn and some stats could be decent. Its just really, really hard to build around mythics intended to go in the first slot because they hamper mana generation to the point where the whole team suffers, even worse when they also have high mana. I’m pretty sure I’d be able to use him, but hes not exactly optimal. I wouldn’t call him worse than Maw (current generation, clearly he is worse than release version) for that reason, because I’d use him differently. Mostly, its the lack of the ability for his match trait to do anything close to what Maw can get off a single devour even untraited. 5 per skull with a skullblob spell when match traits could actually fire more than once off a single board would have been super imposing, but seeing this post match trait nerf he seems more suited to pokes or random cascades. More than likely, I’d use him as a 3rd or 4th slot mana catch in a reckless team that is way more likely to survive barrages and be able to close out the match if things start to go south (but not too far south). Kinda like a better Gargautaur. Everybody loves Gargantaur, right? Right?
One minor addition I’d give to his spell… have him stun first. Annhilation should mean that nobody is coming back from it, so having traitsummons trigger after he annihilates a troop feels… wrong.