I've used a Shattered Pillar/ Soul Blade and a few other Shattered Pillars like pure class, mixed with Devoted, mixed with Paladin (both Gold Pact and Bleak Walker) and mixed with Berserker.
Now that fist damage is fixed (it used to lose out Transcendent after a save load) Fists are the king of auto attack DPS. They have more base damage than slow one handers like swords and battle axes and the attack speed of fast weapons like rapiers and daggers. Power level also directly increases your penetration, accuracy and damage. Bottom line fists are great and you want as high a power level as you can get.
So based on the above you'd want to use a Nature Godlike for the wellspring which gets you +2 power level and can be activated by Swift Strikes and Thunderous Blows so it'll be active pretty much all the time. This gets you +15% damage, +1 penetration and +4 accuracy, all of which is way better than any hat + racial.
A pure class will have more abilities, more power levels, access to high level abilities and faster access to abilities. Getting an extra ability pick every time you gain a power level is really really nice. Just due to power levels a pure monk will gain +1 penetration, +4 accuracy and +15% damage for free. I would not make a pure Cipher, especially a Soul Blade, the synergy that they gain from multiclassing with a melee type is just too great. Even blending a wizard for the instant buffs, illusion spells and summoned weapons or a priest with summoned weapons would work really good and be better than a pure Cipher.
Your shattered Pillar/Soul Blade gets +40% damage from whip at the cost of one ability, and can get +1 penetration from the Cipher passive for one ability. So two ability picks puts you at +25% damage, equal penetration and -4 accuracy compared to a pure monk who will be two power levels ahead. So auto attacking wise its better for the Soul Blade mix depending on the value of two abilities.
If you keep the cipher abilities low, only taking the really good ones and only when the game forces you to pick one (when you gain a power level) you can get some of the monk abilities but you will not have enough to take all that you'd like. Just dumping all your accrued focus into soul annihilation rather than using cipher powers will put out a lot of damage
A pure monk will be the better monk by far. If you want to use lots of monk abilities and passives going pure is a good choice. If you want instead a few Cipher abilities to add some unique stuff to a monk a soul blade is a good choice.
It comes down to playstyle, from a mechanical standpoint both are good.
I much prefer Shattered Pillar to any of the other Monks. Needing to take damage for wounds is not as good as needing to inflict damage for wounds. It's better to give than receive To me a melee Helwalker who gets to taking an extra 50% damage just seems too glassy. Lots of ranged versions that use the Helwalker to fuel a massive spell assault from their other class but that doesn't fit my image of a monk.
I don't have experience with druids and shifters, just don't like the playstyle.
For races a Nature Godlike adds a lot to a fist user. Other than the gimped island Aumaua (faster movement through surf and mud??? really ???) every race is pretty good so pick what you like.
PotD with party companions will be easy enough that you can make any class you like without min maxing and be successful. So make what you find fun and interesting. Triple Crown Solo is a whole different game.
What attributes do you recommend for the pure monk build?
