You people certainly have a skewered vision. The ONLY reason Kisame seems so much stronger than Zabuza is because Kisame was introduced in Shippuden when Kishi had to bump up the action level. Given that they were both members of the seven swords of the mist at the same time it wouldn't be near as one sided as a lot of you are saying, they both died as "true shinobi" the manga said if i remember correctly. However Kisame does have the chakra edge going for him and may win though it would be a hard fight and zabuza wouldn't stop 'til he's dead.
Honestly I feel like Kisame was above the other swordsmen that we've seen lol
I mean as a whole, Zabuza fits the whole "skilled" style combined with his kenjutsu and tactical water jutsu. Kisame however has a sword that drains chakra, has stupidly strong strength, was able to stand up to Bee in close quarters, and has amazing water jutsu. I mean this guy can do anything from 1000 sharks to a huge water shark that absorbs chakra to a huge water dome... just too much