The tax revenue thing is also kind of misleading. First, that number is apparently fixed (based on your wording, I'm not familiar personally), but the there is, presumably, no upper-bound on the actual revenues, so as revenues increase, a smaller percentage goes to education.
Second, vice taxes tend to be regressive, the poor pay a higher percentage of their incomes. Some of the "education lotteries" (state lotteries that benefit education) are basically mechanisms for transferring wealth from the poor to the rich(er). Poor people buy the lottery tickets and the tax revenues go to fund college scholarships for middle and upper-middle income kids. That's not socially healthy.
Given the two points above, there's a real danger that marijuana taxation will be used to transfer the overall tax burden from higher income people to lower income people.