No approval for AP/IB/SAT/ACT, as far as I can see.

No RPN. Every modern graphing calculator needs a mode (doesn't have to be the default) with RPN and a visible (4+ entry) stack. Once people actually learn how to use that for rapid, efficient calculations, they won't go back, but they never learn because all the major calculators don't even offer it as an alternate mode. That's the killer app for "graphing" calculators, because they can show multiple stack entries.

RPN may not be useful for math classes, which tend not to have as many problems involving many sequential calculations, but it's extremely valuable for science and engineering.