The spec specific traits are outrageously good for Aff Warlocks. Demo and Destro have good ones as well. I know plenty of other classes/specs where that is the case too. Sorry it's not interesting for the spec you're playing? Those are all single target traits with absolutely no benefit other than strait ST damage. I'd be surprised if all your spec specific traits actually were dogshit.
Demonology's sure are in general, to say nothing of the oddity with the Excoriate trait being on literally one piece of gear that doesn't drop in a dungeon or raid. But don't take my word for it, let's look at some of the not good ones!
- Forbidden Knowledge -- As much as I think it's interesting, because it changes how you play the spec a little, having to hardcast a 4s spell to get 5-digit damage isn't practical, and that's assuming you don't have Demonic Core stacks competing with the buff which is the major problem with the trait. I'd rather they just make this trait a flat passive effect instead of a 30% chance when you cast Call Dreadstalkers. The double restriction (no Demonic Core procs and the 30% chance of the trait activating) make it impractical. If it was a flat passive effect where you choose when to hardcast it, that would make it a lot more viable, but probably still not enough unless they bumped the trait's damage by another 50% (which would be hilarious burst damage but bad for PVP).
- Implosion -- 264 Haste for 6 seconds (2-3 GCD's) if I implode 3 or more imps. That's a whole 4% haste for 6 seconds, give or take! Yay! Not going to belabor this one.
- Superior Commander -- Get a stack of Demonic Core and 500ish Intellect for 15s after the Tyrant expires. (Every 90s, in other words, so it's kind of a trinket proc.) This isn't really something to write home about, considering that the generic trait outperforms this. The Demonic Core stack is borderline negligible since the ideal use of Tyrant is while you have a Dreadstalker out, so you're going to be getting 2-4 (depending on Dreadstalker cooldown alignment) as it is, rendering this effect questionable. Honestly, I'd rather it be something like "When your Demonic Tyrant fades, your Hand of Gul'dan consumes no Soul Shards for 8s." (The duration would be the stacking value.)