The water elemental no jutsu didn't require so many handseals. At least that's what I think. Remember when Zabuza said that Kakashi tricked him into choosing the seal he wanted. So I think Zabuza was just trying if he really could see his thoughts and made it like a game like rock, paper, scissors. Well not really but...

Don't know If what I just said was correct , but that's how I remember/see things.

And I guess some jutsus require many handseals and some less. I just think they won't bother to draw the same handseal twice. Or I don't know I haven't paid much attention to those handseals. But atleast there will always be the Kage Bunshin no Jutsu and Henge in which Naruto makes those seals.

And atronut, I just love those! They're so cute!