I would say there's a lot more versatile/effective weapon combinations than there are Armor combinations.

Armor pieces that don't provide stat bonuses (CTR, Damage, ASI) are inferior compared to ones that do. As such, a Full Skolver set is better than a Full Skelly set for example, because full Skolver would provide +4 sword attack bonus.

In an effort to promote more armor diversity (and viable armor usage) at minimal change required, wouldn't it be nice to offer Full Set bonuses to those who wear a complete set? Especially to armor that currently don't offer any buffs?

For example, full Dread Skelly Set (Dread Skelly Suit, Dread Skelly Mask, Dread Skelly Shield) could offer a bonus of Damage: High when used in conjunction. Or All Status Resist: Med for full Azure Guardian set. Or Damage Bonus vs Slime: Very High with Royal Jelly Set.

(and give Mad Bomber set Movement Speed: Medium? One can dream...)

Something that rewards players for wearing a complete set to make them on-par with, say Skolver or Vog Sets. Or at least, not pale in comparison to them, given that they cost the same after all. Otherwise, most players go crap, why did I invest all those resources into an obviously inferior set of armor. Then mutter angrily while they heat up an Ash Tail Cap.

Full set buffs feel less abusable than individual piece buffs (since otherwise you may have to look at the different combinations that could make it overpowered) and would be more of an incentive to craft full sets (and thus, varying loadouts) for particular Clockwork levels.