Quote Originally Posted by Flickerdart View Post
Can't use Trapsmith either - your slots have to be 3rd level.
Not so, designers had stated that it was designed for sorc/wiz, hence the phrasing for the casting of haste. But that if they had remembered other classes getting haste at different levels, they would have rephrased the line of the entry requirements.
By your reasoning a warmage can't ever access it, because they treat Haste as a 4th level.
Common interpretation is that you must have spent the previous level using only the Haste spell at whichever level you learn it as appropriate to your class.

Yeah it doesn't flow as well as "Must have spent the entire previous level using all 3rd level spell slots to exclusively cast haste." but rule interpretations and adaptations generally don't flow well. Just ask that Radiant Servant of the Campaign Settings God of the Sun or Dawn over there.