@Reaniel I think most posters here who have been to Venice will say that it is much better to visit Venice independently rather than by cruise ship. It really doesn't matter if the ship docks in Chioggia, Fusina or Ravenna, the transportation to and from the ship eats up a lot of time. It's so much better to go to Venice and stay in Venice for however many days it takes for you to see all you want to see.
We spent a lot of time in Venice several years ago. We visited again this year with Viking and docked in Chioggia. We had no desire to see Venice again, but wanted to visit Murano and Burano. We did that excursion with Viking because the transportation was from the ship via boat. It was a really great excursion and we're glad we did that.
On the way back to the ship, a couple wanted to get off at St. Mark's. Trying to park the little boat we were on was crazy -- horns beeping everywhere, boats cutting off other boats to take their parking space, crowds of people lined up as far as you could see waiting to take a boat to somewhere.
Really, these days, it's best to do Venice on your own. Plus, we enjoyed just walking around Chioggia. It was quite pleasant.