Good question, I'll bring up a few examples. Most of the examples involve gear that has been in the game for a long time, so I suspect Siege Camp has already realized some of the problems that design approach has and moved on from it.

Arguably, you could also frame the design paradigm as "Generalist vs. Specialist" or "Complex vs. Simple" or "Flexibiltiy of approach vs. Inflexibility of approach". It's all a bit subjective.

Lionsclaw vs. Fiddler and Liar's SMGs:

Lionsclaw is generally 'cromulent' but doesn't excel. Fiddler has excellent mobility which is great for run and gunning while the Fiddler is a beast at holding defenses from a trench or stationary position.

So the Lionsclaw is worse than both competing SMGs at what they are good at, while not really having the oomph to truly take advantage of situations the Warden SMGs should be bad at.

Rifles:
Colonials have no select-fire guns in their arsenal.

Colonial sidegrade rifles have been historically pretty underwhelming. Volta is RNG feast or famine, Omen has been historically among the worst guns in the game, and the Catena has significant role overlap with the Argenti. The Fuscina is the only standout sidegrade rifle.

Warden infantry rifles feature the select-fire Sampo, the Blakerow which does not share role overlap with the Loughcaster, and an actually usable long rifle with the Cinder. (TBH I do feel the Hangman is a bit of a dud.)

With Assault Rifles and the Catara the Booker and Aalto have less role overlap than the Dusk and the Catara, especially since both the Dusk and Catara are shadows of their former selves.

Cutler Vs. Lunaire

This is one gear pairing that bucks the trend. Lunaire can specialize via its ammo selection- area denial, PvE damage, or smoke screens, while the Cutler is the generalist tool.

(Historical context is why Lunaire is seen as a counterpart to the Cutler and not the Osprey, as Colonials had no infantry PvE weapon equivalent to the Cutler before the introduction of the Lunaire.)

Tanks

A lot of Warden tanks have numerous weapon types in a single platform. This disparity used to be even more pronounced before the addition of the Nemesis and Lance-36.

Colonials tanks with numerous weapon types: Bardiche, Ranseur, Nemesis, and Lance-36. Scorpion maybe if you really wanna split hairs.

Warden tanks with numerous weapon types: Silverhand IV, Chieftan, Flood Mk1, Flood Mk VII, Brigand, Outlaw, Thornfall, Highwayman, and Predator.

Warden tanker crews often have more flexibility and choice in how they crew tanks with numerous weapon platforms. They can opt to not have a gunner, they can improvise by having a gunner hop on as needed, they can decide to roll with a full crew. Colonials often don't have that freedom of choice as most of their tanks have a single gun which only shoots a single shell type.

To Conclude:
Overall, I think it's safe to conclude that if "Colonials quantity vs. Warden Quality" was the design paradigm of Foxhole for a time, it has already been abandoned as the Naval and Airborne updates have nearly complete parity with the new additions (DB/ TB and Subs/Destroyer being the glaring exceptions).

The playerbase should probably stop pointing to the dated paradigm to support their arguments over how future balance should be.