I think it would be helpful to push the spawnable areas for the mountaineer and servitor groups back to just past the mines, or provide a new route to the mines that would allow you to bypass those groups. I've got a basic tier list below that I think sums up the progression of Kelestian "zones" and will go into why I think this would be a beneficial change after the list, so it makes more sense.

Tier 0 - Night time raiders within the city and the ones that spawn in the Barracks; these are the easiest bunch that provide a place for people to dip their toes into the Kelestian battles without major bodily threat.

Tier 1 - Warriors and Mercenaries in the pathways between the gates and the harder spawn zones, providing enough challenge to lower skilled characters to be exciting without having dangerous lock-in mechanics that make it near impossible to escape when it gets too rough.

Tier 1.5 - The mines, where you have servitors and tunnelers, but in low spawn numbers, giving you a reasonable progression area to fill the gap between tiers 1 and 2. More on why this is a big deal in the detailed description below the tiers.

Tier 2 - Mountaineers and servitors - Found around the outskirts of the mines, providing the next step in difficulty progression from the warriors and mercenaries, and possessing various weapon skills that can make escape especially challenging, be it from being pulled back into the fight, getting your ankle smacked by a claw hammer, or getting tangled up in a chainblade.

Tier 3+ - The battlefields and divers, I'm not sure which would be tier 3 and which would be tier 4, because they're both way out of my league to evaluate.

As shown on the list, the mines are a really good stepping stone for characters that are finding the tier 1 groups to no longer be a threat and want to take on something harder, without the challenge being extremely dangerous or even impossible. With my character as an example, for -most- of the enemies in the tier 1 zone, my main rotation has a 5 success in normal, and the enemies have a 95 success on me in normal (or even aggressive, aside from certain ones). However, if I try to move on to mountaineers and servitors and tunnelers, the power gap is so insane that I can barely handle them 1v1. This makes the mines ideal, because I can go there and have an exciting challenge, forcing me to really stay on top of what stance I'm in and trying to circumvent the enemies' defenses, all the while pretty much always being in critical threat range by the enemy. The servitors, for example, have a 5 on me and I have a 40ish success on them in normal, which is a HUGE jump from tier 1. In a low spawn situation like the mines has, this is acceptable and even pretty fun. I can take the punishment and feel rewarded for the effort, because I'm at least able to take the enemies down, too. But if I'm in the areas outside the mines and get 3 of those guys on me, I get absolutely wrecked. They're going to have 5s on me with constant stuns and knockdowns, and with the variety of disabling moves they employ, escaping becomes near impossible. If their timing is desynch'd, I can't fall back and move away before they re-engage. If I retreat in a direction, they've usually stunned me or knocked me down before I get away. All this compounded with these squares being big enough that there is roundtime moving into them, so you can't just hyper rush your way each area like you can to get to the barracks to be able to get there before anything spawns and engages you. As a result, I typically avoid even going to the mines, because the danger getting to them is too much of a risk to be worth it, which is a shame because the mines -feel- like the area my character should be. This would be like having to go through the Worm Temple to get to the sewers, the path to the destination is just way more dangerous than the destination itself.

So it would be nice to see either the spawnable zones of the tier 2 enemies pushed back beyond the closest mine entrance (currently two exist), or perhaps having the tunnelers dig through and punch a new entrance up into the city where the mines can be accessed more directly.