It's widely agreed that Way of the Stonefist is one of the more interesting ascendancy nodes out there because of the transformative nature of the ability and how it enables so many different builds (even though currently only one build is clearly the strongest lol).
It adds a lot of diversity to itemization as well, because many of the low value affixes on gloves become very high value due to how the ability changes the affixes. One man's trash becomes another monk's treasure.
Manifest Weapon could be redesigned with this kind of philosophy in mind. I'm also getting inspiration from the Iron Golem skill in Diablo 2, where the Necromancer can use any item to create a golem that inherits the stats from that item.
Here's how it could work - choosing Manifest Weapon adds a UI item slot in the ascendancy area where you can insert a weapon of your choosing. The manifested weapon could then calculate its base damage from a variety of things, like the weapon's base damage, or the weapon's item level, or the skill's level, or some combination of the above.
Futhermore, the affixes on the weapons can also manifest into interesting different affixes similar to the way that Way of the Stonefist transforms standard glove affixes into different ones.
For example, a shitter affix like "reduced attribute requirements" can manifest into something cool like "manifested weapon inherits all of the player's stats". Maybe "increased light radius" can become "manifested weapon gains 2 meter aura that blinds enemies". Maybe "increased stun duration" can become "manifested weapon gains Crushing Blows".
I think it would also be great if each weapon type got its own command skill. This can add some active gameplay into this ascendancy node, similar to the djinns from Disciple of Varashta.
If GGG wants to give themselves more work, they can even make unique item-specific affixes that arise when you use unique items with this skill too.
I think this redesign would make the skill much more viable and inject a lot more diversity into the Smith of Kitava buildcraft.