Agreed. a single one hand seal to initiate a jutsu is common, especially if the preparations of that jutsu are already done. But only haku could use multiple one hand seals to do a complex series of jutsus. That's what surprised kakashi. We don't know if it was due to his bloodline which made it easier for him or he trained for it, and we'll never know. Let's move on.
Originally Posted by afro thunda
A bridge towards peace; the will of fire still endures!
Rokudaime Hokage, Rokudaime Rikudou Sennin Uzumaki Naruto