People tend to go towards one set when the game is about branching out.
This is the trend of chaos and black kat, wolver armor, etc. versus specialized armor, as well as the desire to craft as few weapons as possible. They do it because the game gives them the incentive to do it in spite of itself- it's cheaper to craft chaos/seerus/black kat than it is to plan around random scenarios. Since much of the fun to be had is in replaying levels with new gear, it would make sense to force players to branch out.
Buff Every Piece Of Armor (that isn't black kat/chaos/seerus)
I suggest going across the board. Start anywhere. Come up with a nice buff. Implement it. They should all be about as strong as chaos, but in different ways.
Doing this will provide further incentive for players to craft armor. They wouldn't have to get chaos/seerus or get the wrong end of the stick. Most of the armors can be fixed via stat gains/losses, but a few more stats would really help out here. This can all be done later, but the process of fixing up old/bad armor, say, once a month, would be the real change that's needed.
Raise the drop rate of orbs and fire crystals... but also the need for them.
Currently the knight only needs one set of armor and a single weapon to progress past the hall of heroes. This is likely intended as a minimum amount of gear, but it is often treated as the maximum amount one should craft. Hence, we triple the requirements. 3 sets of armor, 3 shields, 3 weapons. Then, we double the drop rate of orbs and fire crystals. That way, newer knights get to the Hall of Heroes, grind about the same amount, and come prepared into the new tier. This should carry over to radiant fire crystals, such that they are able to heat three times the gear with twice the fire crystals.
Make status effects harder on the knight when not resisted, and easier when resisted
The knight has about 5 degrees of resistance. Here is what I'd like to see happen-
Negative Resistance = should mean the knight is on death's door immediately. Think curse length status effect.
No Resistance = should mean the knight is heavily harmed but not quite dead.
Some Resistance = harmed greatly, almost as if no resistance as this is chaos cloak + seerus
Normal Resistance = i.e. 2x vog for fire; +8; the knight should be barely touched
All In Resistance = 2x vog + trinkets + UVs etc.; the knight should be immune
The actual values players use for these are-
Negative anything
0
3
9
12+
Where one point is a low. All this takes is tweaking some numbers, and would make the game much more dangerous for glass cannon users.
I really like those ideas. Though, we have came so far with our current system and metas that i dont think its a good idea to change everything like that, at this point of the game's lifetime.