Imaber's page

1d+4, 2d+6 and ,3d+8 are enough to make better than power attack and to make it just about on par with gleaming blades version.

The thing is it really isn't on par. Even in a scenario where you need a 15+ to hit on your first strike, a situation that should favor titan breaker's 0 attack penalty, gleaming blade does significantly more damage. Assuming a d12 weapon, at level 4 its 12.25 avg for gleaming blade and 9.3 avg for titan breaker. Level 11 its 20.25 for gleaming, 16.05 for titan. A 20% deficit in dpr when taking the titan's ideal situation is not good. Things tilt more in the favor of gleaming blade against targets that require less than a 15+ on the die to hit.

If we instead assume titan breaker's effect is 4/6/8 damage per die, its average damage at level 4 becomes 10.5, and 19.65 at level 11. Even with the stronger interpretation it lags a little bit behind gleaming blade. But at least with this interpretation I can see titan breaker's ability to hit constructs with their spirit damage making up the gap between them.

I really can't see them adding the flat 4/6/8 damage text with the intent of it not scaling with number of damage dice. Writing it the way they have way doesn't really make it easier to remember at a glance, because writing "you get x damage per weapon damage die" and then immediately going "ok now you don't get that bonus at all, but instead you get a flat damage bonus that doesn't interact with weapon damage dice, plus a die of damage" is way more confusing to a reader than letting the two damage bonuses remain listed separately.

Not to mention the entire ikon would be basically a strict downgrade from noble branch, as noble branch's transcend would do more total damage than titan breaker's and doesn't require a 2 action commitment.

Unless there was some heavy miscommunication going on as to the general power level of weapon transcendence actions, I think its much more likely to be a wording issue than a balancing one and that it should read 4/6/8 additional damage per weapon damage die.

Definitely feels to me like #2 is what they mean. Extra weapon dice from abilities and such are never counted for +X damage per weapon damage die effects, only the single base die + dice from striking runes apply for those.

The ability saying that the spirit damage increases makes me think that the flat number listed (4/6/8) is supposed to slot in the place of the 2 in the immanence description, so it would be 4/6/8 damage per weapon damage die.

It's a much stronger version of power attack, but the class doesn't get any other inherent damage boosts, and having to juggle your spark means that this ability ends up with an action economy most similar to a spellstrike.