The Iberians revolted plenty, and they weren't brought into the Roman state all at once, but over the course of several different wars. Ignoring the several revolts during and immediately after the Punic Wars, there were the Lusitanian Wars, which saw the Lusitanians revolting several times and having to be pacified each time, and Augustus' campaign against the Cantabrians. This isn't even mentioning weirder wars like Sertorius' war and the extended conquest of the Celtiberians, which took a century to complete. It's important to realize that Spain was not conquered all at once like Transalpine Gaul was, but over the course of several centuries bit by bit. States within and still outside of direct Roman influence had plenty of opportunities to revolt or resist, according to their relations with Rome, and many did so--the region would not be fully pacified until Augustus completed his campaign in 19, B.C. We don't see major revolts after Augustus' rule, the way we do in Gaul and Britain, because Spain was conquered so much earlier and most of the dissent had been taken care of--the region was in more or less constant resistance for pretty much the entire 2nd Century, and much of the 1st as well.