I think this spell is more potent at low levels especially since you will cast in it conjunction with spells like Haste and Spectral Hand, but I do not think it is broken.
For a Wizard, 5th level is when he can first do this type of combo. It takes a 3rd and a 2nd. He casts Spectral Hand ahead of time (often possible).
60% * D8+ 5 (assuming he hits with touch attacks 60% of the time with the +2 from Spectral Hand)
So, he only averages 5.7 points of damage with no save in one round, but he can do this at range every round for 5+ rounds (depending on how often he misses). That's most of a combat. He can also critical upwards of 26 points of damage in a single round. When compared to his crossbow that does an average of maybe 0.9 points (assuming a 20% hit chance), it does some significant damage.
Against another 5th level Wizard with 14 to 29 hit points, that will take him out in 1 round best case, 3 to 5 rounds on average. 2 to 3 Magic Missile spells will also typically take out the same 5th level opponent Wizard in 2 to 3 rounds unless he has the Shield spell memorized.
When you throw a DC 15 or higher Fort Saves against Daze on top of that, there is a fair chance that any non-spell caster opponent cannot counterattack on the next round at that level.
Or, combined with Mirror Image, it is like doing D8+5 combat damage (Fighter level damage) with touch attacks (better than Fighter level to hit).
Effectively, any way in which you can drastically increase your defense (Mirror Image, Improved Invisibility, Stoneskin) or increase the number of attacks per round you can get with this (Haste, higher levels) or give yourself range (Spectral Hand), can make this spell a lot more effective than what it sounds on the surface.
Hasted for this doubles the average damage at lower levels.
The other time this starts becoming more effective is 12th level when the caster can do upwards of 3 attacks per round with this when Hasted (full round attack plus partial action attack). This can result in 50 points of damage per round without criticals.
But, the best use of this spell is to finish off opponents that are already injured 80% or so.
The real issue here is that this spell can be significantly increased in effectiveness due to other spells. Does that make the spell broken?
I do not think so. This spell is good continuous damage, but it is slow. Yes, if you use Spectral Hand and attack from range and behind cover (or with good defensive spells), you will take out one or more opponents within a combat with only a few spells. But, taking out a few opponents in a combat is not that big of a deal.
For a Wizard, 5th level is when he can first do this type of combo. It takes a 3rd and a 2nd. He casts Spectral Hand ahead of time (often possible).
60% * D8+ 5 (assuming he hits with touch attacks 60% of the time with the +2 from Spectral Hand)
So, he only averages 5.7 points of damage with no save in one round, but he can do this at range every round for 5+ rounds (depending on how often he misses). That's most of a combat. He can also critical upwards of 26 points of damage in a single round. When compared to his crossbow that does an average of maybe 0.9 points (assuming a 20% hit chance), it does some significant damage.
Against another 5th level Wizard with 14 to 29 hit points, that will take him out in 1 round best case, 3 to 5 rounds on average. 2 to 3 Magic Missile spells will also typically take out the same 5th level opponent Wizard in 2 to 3 rounds unless he has the Shield spell memorized.
When you throw a DC 15 or higher Fort Saves against Daze on top of that, there is a fair chance that any non-spell caster opponent cannot counterattack on the next round at that level.
Or, combined with Mirror Image, it is like doing D8+5 combat damage (Fighter level damage) with touch attacks (better than Fighter level to hit).
Effectively, any way in which you can drastically increase your defense (Mirror Image, Improved Invisibility, Stoneskin) or increase the number of attacks per round you can get with this (Haste, higher levels) or give yourself range (Spectral Hand), can make this spell a lot more effective than what it sounds on the surface.
Hasted for this doubles the average damage at lower levels.
The other time this starts becoming more effective is 12th level when the caster can do upwards of 3 attacks per round with this when Hasted (full round attack plus partial action attack). This can result in 50 points of damage per round without criticals.
But, the best use of this spell is to finish off opponents that are already injured 80% or so.
The real issue here is that this spell can be significantly increased in effectiveness due to other spells. Does that make the spell broken?
I do not think so. This spell is good continuous damage, but it is slow. Yes, if you use Spectral Hand and attack from range and behind cover (or with good defensive spells), you will take out one or more opponents within a combat with only a few spells. But, taking out a few opponents in a combat is not that big of a deal.