Apologies if I'm beating a dead horse here. I promised I would only do that on blue moons.
Ulmar's Bionic Steam Arms are actually pretty solid in nearly any Gan'trak deck. Fearocity is likewise good despite its quirky element/discipline pairing: usable by warbeasts, quite a few Danians, and even a good many UnderWorlders. Let's not forget that the correlation we have today of two disciplines attributed to each element wasn't exactly established yet; take Unsanity's air damage for example.
As for cards I think were done poorly...
Original Tangath Toborn.
He was among the bravest and baddest dudes of my tribe in the show. I feel like I could file a claim because what they did to his first incarnation was a crime. You needed max courage to use a Ring of Na'arin. You needed at least high power for Elixir of Tenacity. Even with that and max energy, anything stronger than a sniffle from Brathe would have been a one-shot kill. That's not just because Brathe was a legitimate house that I rarely saw used. He could have been and was being easily beaten in single combat by Bodal. BODAL. You know there's something wrong when Perim's future savior is losing most of his battles with a shelf keeper. It took Stone Mail and/or average to minimum energy w/ Melody of the Meek to even make him slightly competitive. Oh wait, Discord if Disarming was a much more common sight back in the day.
Something that didn't make sense to me in the long run was Lake Ken-I-Po. You mean to tell me the dryland tribe who has perfected the most powerful negation Mugic gets punished hardest by the home of their best muge? And the initiative even spits in our faces? When Naj FF is powerless to stop an Unheard that will lead to an Aa'une rampage...
How about Catacollision? Discount Apoc-eclipse and then we invented Landgore.
Chromatic Postlude if only for the fact that it's more useful in any tribe except the one that created it.
Crown of Aa'une's significant flaw is that is doesn't begin the game face-up. That is a very big deal. Don't even give me the "You can flip it up with Mugic/abilities" bit. Either you keep a Mipedian around (probably Epitrinne) to cast a Gear Glissando, you wait four score and seven years to draw that Sirroco that's only ever used by me for Ravita Flowers, or you don't use Garv because the Crown doesn't like things it can't mentally dominate. And then you're vulnerable to the not-uncommon problem of Surprising Riffs just twiddling the gear back to dormancy or other Mugic and abilities destroying it outright, not to mention Glissando being dispelled.
I was planning on going down the list alphabetically, but I'll just leave off at Poison Panic. I'm not exactly mad that Invader's Tactics, Kha'rall Crush, Rage of Aa'une, Eidolon Advance, Flood Force, Outfreeze, and Essential Evaporation are all strictly better and lower rarity in terms of damage; I get that the game had power creep over its expansions. I've seen it seemingly hundredfold trying to come back into Yu-Gi-Oh! as the old school troll I was. I intentionally exclude Rip Tide from the list because it was printed twice earlier, but it's strictly better too. But the fact that Panic's outperformed by all of those attacks and has a drawback for making a slight attempt at consistency makes me want to feed myself to Toxis headfirst. Even Iron Balls has more use than this, and they're not even in the same league of attack type.