What makes me sceptic is that we've seen the "zombies stop spinning or running in circles" fix in previous releases and it never worked. So they might be fixed, but there is a good chance that they still do it. Not to mention bears and dogs and that bug where the vulture floats on one position and constantly changes direction by 180 degrees for a few seconds.
Also Roland I think the main thing that would need to be done before it should even be considered to add water vehicles is change the water to actually be like water, not sticky semi-static goo. Right now I can still with a couple wood frames split the water like moses and while it does actually flow a bit, it does at the speed of a turtle with asthma. Even the player movement speed in water reminds more of swimming through thick goo rather than water. Minecraft (and I once again apologize for getting ideas from MC stuff, we all know its not a good game at all) once had a mod that added finite liquid. I think that would be a very interesting addition to 7dtd, especially once we have like small mountain ponds etc that can actually run out of water if its finite, since every glass jar basically takes half a liter away.
Alternatively, water could be simulated by essentially having alot of circular entities (in terms of hitbox, more of a cubic shape in terms of visuals tho) that work basically like a ball bath. You fill a river with thousands and thousands of these and you essentially end up having a finite "liquid" in the game and even better; due to this design you could even make that flow down a hillside without looking like blocks. The game would only ever have to render the top layer, and digging from a cave below up into a river or lake would mean that the cave gets flooded properly.
The main difficulty I see with this is how the game would treat these "entities", since I imagine it would impact performance alot if they would be actual entities. Perhaps a new type of "entity" that doesnt work like others do and doesnt take many resources whatsoever. I am not sure about this tho. But its a concept that at least in theory could work perfectly fine.