This can be covered in trinkets. Like the gloves. Boots and belts probably not, but you can get a fancy necklace.

The things such as the perks you mentioned should just go alone into trinkets. Just less complicated.

Making gear too involved just makes players less likely to make a variety of gear. We have 3 varieties of defense (helmet, armor, shield) and 3 varieties of weapons (sword, gun, bomb). When we separate armor into several more things, it's sorta convoluted. Visually it would be a lot of model work since it would affect every armor in the game. I would rather encourage players to make 3 sets of armor for different scenarios than spend another 6 days trying to pass the hall of heroes and have them quit at the 3* one.

As it stands I love the simplicity of the game. It has a cute and easy to understand game on the surface with a lot of depth underneath.

And for your "smart players love calculating"... Well, we have those players, and they're still calculating.

What about the orbs?

If you're complaining about UVs then that's a different monster to handle. The armor system in the game is alright, however the defense values they give are lackluster.

As it stands, you only need 12 orbs of alchemy to advance at every hall of heroes. Unless these additional items are like trinkets (not required, but do things), then it's more reasonable, as following the current logic it would be 21 orbs per hall of heroes. I can't see many players wanting to farm orbs with their current droprates for that long.

Additionally, buffs in the game are already so widespread it would be more worthwhile to nerf all the other things just to make these items be worthwhile. That might not be too bad in practice, however game balance would be out of whack for a long while.

What you want is an expanded trinket system with a visual effect on your knight. If we were to have something like this, it should be on top of our current sets, but give a positive and a negative.
Basically, you have 3 free trinket slots with a buff and a nerf, and the two paid trinket slots that give a buff only. New slots would have universal effects (eg. +2 shock -2 freeze), as well as specialized effects (eg. boots can affect movement speed and dash timer).

You would use these items to min-max your gear. I would say make these new items affect bonuses last, meaning if you have +6 from black kat and some gloves increase ASI by 1 and damage by 1, then your damage would be capped out at ultra.

This adds the "complexity" you desire without increasing the required grind, and doesn't require a huge armor overhaul to do either.