Ubisoft is Ubisoft, and they do have a track record of being able to ruin things. However, hopefully the difference between this and projects Ubisoft fully control are Matt and Trey. I'd assume they have a lot of creative control in terms of the story, flow and direction of the game. I'm not under the impression that they have simply sold off the South Park licence for Ubisoft to do whatever.
Ubisoft alone might already have released a "bad" version of the game at one of the earlier launch dates to cut their costs and cash in on pre-order marketing for a large IP game. However, hopefully there is a contract in play that lets Matt and Trey have some say in the final product, and if the quality isn't there, they can refuse a launch. So, even with many delays I am hopeful for the simple reason of Stick of Truth, and how good that was.