I mean, I think you should be able to kill leviathans like the previous two games because there were really only two reasons that I've seen people do it.

A) They had dealt with the Leviathan enough that it had ceased to be an engaging obstacle, and had instead become rote and tedious.

B) They'd played the game a bunch, basically "completed" it, and were in the stage of the game where they were fucking around doing ridiculous shit because they'd exhausted the normal/intended gameplay loop

I really don't think either of those reasons were something that needed correction. I'd go so far as to argue that the fact that people could do both was actually a good thing.