Currently, knights at tier 2 can earn a lot more crowns per energy spent than those at tier 1 when adventuring in the clockworks. That means that when the crystal energy price drifts high (meaning ~5k or more), tier 1 players can no longer make a profit by adventuring on crystal energy. That's not merely an issue of "you need to pay money if you want to keep playing", it's an issue of "even after paying money, you are better off selling the crystal energy you bought than using it to actually play the game". It actively discourages players from buying or spending crystal energy, right when they're new and impressionable. This is bad.

Conversely, knights at tier 3 can earn pretty much exactly the same crowns as knights in tier 2. The materials are better, but that makes little difference to overall income, especially if you're in a group (some 5* mats are worth thousands, but the party collectively seems to average only one or two from the entire tier, that's really small percentage-wise). This makes players feel like they're not progressing even while they craft super-expensive gear, and it even encourages five-star players to hang out in tier 2, where the income's just as good, but it's easier to find groups and the risks are lower. This is also bad.

So here's how I think it ought to work:

1. Crowns earned per energy spent are pretty much the same everywhere in the clockworks
2. But in the more challenging parts of the clockworks, you can convert your energy into crowns faster

One simple way to do this would be to multiply the drops and the elevator fees by the same amount (double the entry fee, double the rewards), but some of it could also come from clever level design, giving hard monsters strong attacks but low hp, etc. But the basic point is: don't mess with the exchange rate, but DO mess with player income.

This way, low-level players don't get locked out of actually playing by an unfavorable exchange rate; they can buy crystal energy on the exchange and make a profit, just like anyone else. But the higher-level players who are taking on more difficult challenges are still rewarded, because they make more money for each hour that they play. The players who CAN beat tier 3 are still encouraged to do so, but the players who can only beat tier 1 still make progress the whole time they play.

As an interesting side effect, your daily mist allotment translates into more hours at low levels than at high ones. This means the new, impressionable players who just want to try the game out and are scared of the whole "crystal energy" concept get to play longer for free, but as they grow up you gradually wean them off of mist and get them to do more and more of their adventuring on CE (assuming they want to play an equal or longer time). Sounds like a bonus to me.

I don't know how you could balance energy gates on this principle. I guess you'd just have to leave them as something that's only opened by people who don't use up their mist or who are desperate for rare box drops, like they are now.