Dragon combat in Broken Valley required paying attention, but wasn't terribly difficult; most human combat was relatively easy.
Defeating Geshniz the first time I got an epic shield and axe. The second time I got an elder helmet (+10 Vitality, +10 Spirit, 4/0/4 Melee/Ranged/Magic Armour Rating), earrings (+2 Evade) and axe. A third time game an epic axe and a charm, so I reloaded the save with the elder helmet, for an extra 35 HP and Mana compared to Amdusias' helmet, though with a loss of the +2 Mana Efficiency bonus (in combat after that, the difference was noticeable, but I didn't come close to running out of mana).
In Rayhun's headquarters, approaching the main room, an explosive arrow at the first opponent in range brought everyone out, leaving their leader alone inside. The first time I defeated him he dropped an epic cuirass (+9 Vitality, +9 Spirit, 0/13/6 Melee/Ranged/Magic Armour Rating), necklace (+3 Fear) and sword. The second try he dropped an epic belt (+68 HP, +71 Mana, +5 Critical Chance) and an elder belt and shield that were mage focused. The third try produced an epic bow (with damage not close to the Bow of Orobas) and a couple charms.
While the stats on the epic belt were only a modest upgrade to the one I got from Xanlosch, it did come with a level 8 Healing Aura, so I would have taken that. However, after a break to make supper, I decided to try one more time, and got some epic gauntlets (+9 Vitality, +9 Spirit, 0/6/4 Melee/Ranged/Magic Armour Rating) and leggings almost as good as the ones I was using. I had legendary quality gauntlets on, so immediately upgraded; one enchantment on the epic gauntlets was level 10 Increased Mana, so I left that and changed the other to level 9 Life Line.
The mine was much more difficult than the other human areas in Broken Valley (which were easy), when there were multiple archers (using Stun Arrows) accompanied by other opponents. I didn't die clearing most of the mine, but did come close a couple times. Unfortunately, I didn't have very many potions when I entered Broken Valley, and the rate I was using them went from occasional to frequent (maybe I was just out of practice having to dodge arrows, but any large groups in the mine I needed one or two potions for). When I reached Ba'al I started off running around the outside of the chamber trying to take out the various minions first, and was doing ok. However, at one point I decided to try to fire off and an explosive arrow and then heal, when I should have done it the other way around; there was a demon much closer that I thought behind me, and I died before I could heal.
After reloading and teleporting back to the battle tower to make some potions, I returned to the mine and stayed in the initial hallway rather than run into the main room. Ba'al could hit me there (even if I moved back out of sight or hugged the walls), but this made things much, much easier. I took out the closest couple of opponents, then summoned my creature, who got the attention of a few more (as did an exploding arrow, after moving a bit into the main room to get in range). Having them come to me made them much easier to take out (demons couldn't Rush Attack me, and when they got to the hallway I could let them get close and kill them with Splitting Arrows; in the main room I could not afford to stand still long enough to let a demon approach). I didn't need any potions, just used the Healing spell a couple times. I tried again, summoning the creature right away, but it ended up attracting the farther opponents before the closest were dead (though that didn't make the fight much harder).
In D2:ED as a duel wielding, strength based warrior, I entered the main room right away, and attacked / Rush Attacked my way around the outside of the room to clear the lesser opponents before focusing on Ba'al. Who would have thought such a successful warrior strategy would be less than optimal for a ranger in DKS?
The first couple times I defeated Ba'al he dropped some elder and epic equipment unsuited to my character, then an epic ring that was a marginal upgrade (+71 HP, +6 Critical Chance, +0.1 Mana Regeneration, with a level 6 Healing Aura enchantment). Encouraged that he might give something good, I kept going (they needed to die an extra couple times anyway, for having the gall to kill me the first time, just because I rushed in without due care). The next tries gave epic earrings (+3 Mindread) and another ring almost as good as the previous one (no healing aura, but there was a divine vitality charm in the loot). Figuring that was as good as it was going to get, I almost reloaded to take the earrings, but then decided to give it one more shot. That try gave a divine spirit charm, an epic cuirass (not as good as the one I had) and an epic bracelet that quickly replaced my previous one (+3 Splitting Arrows, +10 Dexterity, +6 Heightened Reflexes); one enchantment was level 10 Static Charge, so I changed the other low level enchantment to level 9 Magic Damage Aura.
I was almost up to level 34, so I left the sigil in the loot bag, to come back for later (when I start turning in quests).
Heading to Kali's fortress I levelled pretty quickly clearing the anti-dragon defences. In the headquarters, Kali dropped an epic ring the first time I killed her, which would have been a slight upgrade. The next try gave an elder axe and (mage) bracelet, and an epic (warrior) bracelet. The third try gave an epic belt (+71 HP, +6 Critical Chance, +0.11 HP Regeneration), which I equipped; I'm pretty sure the loss of 62 mana from the previous belt will not be noticed in most situations, so the small boosts to HP and critical chance should hopefully be worth it.
Remembering the well cave, I decided to head to High Hall to take another crack at Zagan. This time it was easier, but still a bit of a pain. I used pretty much the same technique as before, concentrating on getting the number of flying opponents down first, to allow a run at a nest. Apparently clearing the fortresses was good practice, as I rarely got hung up on obstructions, etc. I still had a bit of a problem trying to target specific opponents, where pausing the using the right stick could, for example, cycle between demons above me, when I was flying directly towards a nest (and was a lot closer to the nest than the demons). In these cases unpausing and getting a little closer would generally allow me to target what I wanted, though the delay could help my opponents.
In the first 3 flying fortresses, after clearing the anti-dragon defences and double checking that I completed everything in human form, I didn't catch much that I missed the first time through (there was a ground opponent left in Stone's fortress, an almost dead flying opponent in Raze's, and two pairs of ground opponents in Kali's, along with a crate or two in each). In Keara's fortress, there were a couple larger groups of ground opponents (4 to 6) and a couple smaller groups (2 or 3). At least the larger groups were in fortifications that were mostly blocked off by wizard towers, and I'm pretty sure one of the pairs of black ring members was, as well (I remember looking for them the first time through the fortress; they showed up on the mini-map in a particular spot, but I could not find them flying up the to area directly above or jumping down to the one below).
After clearing the main part of the headquarters, I tried opening the door to the inner section 4 or 5 times, without naming any of the statues. I ran fairly low on mana a couple times, due to concentrating on Explosive Arrow and Splitting Arrows if there were fair sized groups (to damage as many opponents as possible). It took awhile, though, so hopefully mana will not be an issue in normal gameplay.
It took 15 minutes to clear the headquarters again, giving 13k experience; if I wanted to do that for another half hour, or so, I could have reached level 35. As exciting as that prospect sounded, I decided to pass, and just solved the puzzle.
Keara didn't drop anything worth making note of, but I did kill her a few times, just trying out different conversation options concerning her husband's ghost. In D2:ED I told Keara he wanted to wait for her in the Hall of Echoes; this time I finished by ignoring his request to talk to Keara on his behalf (I equipped my jewellery with Wisdom bonuses that time, which added a little bit of challenge to the fight, sorely lacking in earlier tries).