Despite the crowds, and there were a lot of crowds, this was a worthy stop. I stayed on the outskirts of Venice in a funky campsite, in a kind of lightweight cabin, for 1 night.
It turned out one day walking around the centre was plenty of time. It is a fun place to get lost (and you will get lost) but you never stay lost for too long.
Luckily it was pretty easy to escape the crowds and the expensive restaurants / stalls simply by walking around a couple of corners.