Kai-- perhaps it used to be that way-- but the treatment of functions from a conceptual stance (rather than a procedural one), the inclusion of trigonometry, and advanced concepts which used to be in a rigorous GEOMETRY course, just to name a few differences. Some of those things are pretty old school-- and the sheer volume, pace, and rigor in the course catches many students off guard, and always has.
It sounds to me like you're describing what is typically taught in precalculus. I'm teaching Algebra II right now and taking precalculus (in preparation for teaching it--or at least providing human-in-the-room help--next year) and am seeing a huge jump in complexity between them. But between Algebra I and II, not so much.
