Do you mean a 2+ star kunkka? If not, you must have played a crazy 3 game sample. On a conceptual level I can’t see how having 2 or more would be good, nor have I seen people win with that yet.
If you are able to get a 2* kunk you play it, but playing a 1 star in the late game is a bad move (a good opponent will be able to kill him before he gets the boat off). So unless you happen to have 2 2* kunks I doubt playing 2 or more could be competitive.
On the larger point about balance, I agree it will improve over time. I think overall the balance is pretty good, and not notably worse than the original mod (if anything it’s better). You might need to keep at it to see that.
PS - there are two hard counters to the boat: kill the kunka quickly, or better yet space out your teams position in the late game so that the boat is very limited in how many guys it can knock down.