Without being able to see it, it sounds like they did not get good exposure of all the aggregate. Disappointing indeed. If this is the case you don't have many options except another acid wash or "hot startup" and lots, and lots of brushing. I don't like the hot start idea to be honest, but I would press the installer and let them know how unhappy I was. See what they might offer as a remedy. No finish will ever be 100% as good as a sample swatch, but it should be very much like it in a vast majority of the pool. Even the best will have "cream spots" and blotches, but they should be minimal.