Companions aren't scaled to be 1:1 with the player character Arona uses a mastbreaker one-handed, Brint dual-wields heavy weapons, they get more ability points and use powers and items we'll never be able to use. And in return, they're static. Cait will never graduate from Heal to Greater Heal. Brint will never be able to switch a power out for a specific fight.
So it's not useful to look at a companion's equipment and compare them to our own. Because companions and their equipment aren't balanced to be equal to us, they're balanced to fill a role. And if a little bit of bullshit needs to be added to a companion for them to perform that role, the devs can do that because they're not the main character.
I fully understand your points and agree with them. However, my point is not to compare the companions with the PC. Just to have a better Idea what our companions are capable off.
But before I go into detail, a big disclaimer: I enjoy knowing such things and I understand that these informations are not that important to most players. Like they say: "Knowing is half the battle". For me, knowing is half the fun.
I think it would be beneficial to add the item cards. Best examples are Kiyoko and Queenly Raiment Ryn. One is a mage, the other a heal/bless bot, so you don't really expect them to do meaningfull dmg on regular attacks. In truth they can hit as hard as Arona and Brint. On the other hand Cait (minus Hexleather) and Berwyn deal low dmg, as you would expect from mage/support roles.
So, if you could see the actual stats you would notice that Kyoko deals holy dmg (ATM the best dmg type in the game) and scales with willpower. This is a godsend especially on the Onmyodo set, since both fire and blight are crippled against demons. Or that Ryns spear does almost Griefmaker tiers of dmg.
With this you can see these nuances and it can prevent misconceptions.
For example Brint/Brienne. IIRC he/she doesn't actually dual wield, only if you use the "giants reach" power. For every other attack they use the "Axe" which is just a renamed poleaxe. Or hexleather Cait. Her salamander spellblade is the exact same weapon as the spiraled blade. If aquired through the editor, both have the same elemental dmg cycle. But does Caits weapon cycle? Is her elemental dmg fixed? Is it the same on each day as your spiraled blade? Can the cycle be rigged or resetted by switching sets or not having her in the party? Another example is, how much holy dmg does Aronas Nightfang deal? Or I initially thought that warhides Arona uses a weakend mastbreaker, since it can't be used with a shield.
Again, this is just me enjoying information. With item cards, I could just check if Hexleather Caits dmg cycles or not. Instead of doing tests, asking in the forum or asking developers directly. In the end, the addtion of item cards would be unnecessary for most players. But it would make me alot happier.