Treasure Vaults almost always give less crowns and heat than the other levels (graveyard and whatever else there is). You stay there for almost no time at all, and the crown reward in the hallways are low, even on stratum 2, 4, and (well, I'm guessing 6, but I haven't been there). I think four things could change:
Treasure boxes: I've seen before the suggestion of a third treasure box, maybe blue or gold, which are even more likely to drop an item, token, or larger amounts of coins and heat. Maybe a few rarer boxes tossed around the level, but only a few.
Enemies: The enemies would have to be a special kind though, because Treasure Vaults are sort of like a break from the rest of the clockworks. My idea for an enemy is similar to the moneybag enemies in the 3D mario games (64, Galaxy, etc.). They run from the knights when seen, and can hit the knight (for medium damage, so there's still some risk) if they get too close. When killed though, they would explode in crowns and heat. There would also only be a few of these, about the same amount as those Kleptolisks.
Crowns: The crowns in the halls should almost never be the coins worth only one crown. Maybe at depths 1-3, but eventually they should change based on the level, to eventually being worth ten every time (and occasionally 25).
Area: The area could be bigger, or, even better, have special gates to get to the boxes. I like puzzle gates, and there aren't enough in the game that are actually difficult. I think there should be more puzzley stuff in the Treasure Vault. This wouldn't add to the amount of the reward, but it makes the reward more... rewarding.
In summary, all of these would add to the crowns, heat, and the fun of getting into a Treasure Vault. Another thing it would do would add to the time spent there. Doing puzzles, tracking down the moneybag enemies, and finding all of the blue boxes (Which would be around the level or behind puzzles, not in groups). Another thing is that even though it sound like it might be too much, the amount could be changed to at least make the crown amount on par with the levels around it. How much do you think this would have to be changed? Do you think this is a good idea?
There's a reason why they didn't make it worth it.you risk to get more.it's a lower chance of getting grave yard than treasure vault.it's just chances.lower the chance of a room =more profit.