Okay, tried the "typeless knight" playstyle again, this time with an Earth Knight.
This character took the now-working Dancing Weapon and became disgustingly powerful.
The big powerspike of this character definitely came around level 30-40, where I was able to kill High Sun Paladin Aeryn by standing next to her and holding 5. The same went for the Inner Demons debuff - turns out i can't harm my demons, but they can't do anything either.
However, the character struggled a lot with the High Priest for reasons I'll explain later.
The other incredibly strong part was the early game - turns out all non-caster enemies can't really cope with you having 45 armor with 60% hardiness at level 5.
Prodigy-wise, I found Eternal Guard to be rather nice, as it eliminated any need to gear for accuracy due to counterstrikes and helped keep block up near-permanently. It also let the "damage on block" egos on shields contribute a rather meaningful amount.
Adept was thrown in as a "I need my percentage chance skills to trigger more consistently", and it performed fairly well there. It also helped (along with my willpower gear) to supercharge the Surge mechanic from Eldritch Wardings.
Feedback on specific skills:
Earthlink is nice, but can lead to problems with map generation, such as putting hidden vault entrances into walls, leading to them being inaccessible because you dig the wall, destroying the vault, when you enter them. It also allows you to walk through a lot of stuff on the worldmap - and it turns out the mountains south of Kruk Pride are diggable

Dancing Weapon feels a bit weird right now. First of all, it spams your combat log with constant weapon swaps. Second, would this not lead to the weapon-swapping bonus from the swapping talent tree being permanently active?
In addition, the playstyle of Dancing Weapon changes severely as you level the talents in the tree:
- you start off able to just hold down the wait button and let the weapon work for you
- when you learn the defensive dance, that gets completely lost and you have to bump again
- and when you get the reactive dance, you're back to just holding wait, except it's now better defensively and worse offensively.
Also (although this is probably an Earth Knight exclusive issue), the weapon did not seem to retaliate when something else blocked the damage completely.
Oh, and please mention somewhere that the weapon will only counterattack if the enemy is in range of Weapondance.
The "On Guard" buff seemed to break sometimes, granting me 200+% damage reduction temporarily (not sure why.)
And now, Eldritch Vigor and the problem with the High Priest:
The skill is extremely nice. Between Wardings, Vigor and my high willpower, debuffs ticked down at three times the rate while holding wait.
The problem here is the healing is based on your life regeneration - if that is reduced below 0, pressing wait will drain your life.
Given that the High Priest constantly reduces your life regeneration by 50+ per turn due to high levels in the entire Dark Sustenance tree, I had to flee several times during the fight to heal back up since waiting (which was my main form of defense) was actively killing me.
Finally, thank you for adding a "untyped" preferred energy. However, this damage type has a mistake in its code - if you kill the enemy it is supposed to be projected on (such as killing it with Eldritch Strike), you'll get an error as the damage type tries to check whether it's hitting an ally, but finds nothing. (there's an "if target then" missing there)
EDIT: Okay, it seems the swapping benefits from Seamless Exchange don't work.