On the contrary. The AI in A16 didn't have a particularly pronounced path-finding but their actions were not random. They ran directly towards the target and hit everything in the way.
In A16 the side they were spawning at and therefore attacking was randomly picked but fixed over the whole horde night. So any base had to have maximum protection from all sides but they only attacked one side. If A16 zombies had only been enhanced with a random attack angle though they would have been totally ineffective as they would have distributed their attack power on ALL the spikes of all sides instead of only one side.
There are multiple differences in A17: One is the bonus they get when they attack one spot. This is the change that even in A16 would have brought any design based on a ground floor cage to its knees because the zombies would get through too fast. And the destruction mode added to A16 would have made exploity stilt bases impossible. The third change was the path finding, the fourth the random angle they spawn at.
Of all those changes only the path finding makes A17 LESS random, and turning that off would make the zombies behave more random and more like A16.
There are a few ways that A17 could enhance randomness for basic zombies:
1) They could make the length of a path
much more expensive (for the pathfinding of the zombies). The more expensive you do that the more you simulate A16 behaviour. Also remove the random spawn angle and A16 behaviour is fully back.
2) They could randomly decide if they use attack mode or destruction mode. But then the next question is at what time do they randomly decide this? At spawning or when they have arrived at the base? Before or after following the least expensive path to the player?
3) They could make a path calculation but randomly decide which of the best paths they ultimately follow, the best, the second best, ...
What you seem to be warning about (correct me if I'm wrong) is basically version 1. I hope it is clear now why I consider it to be similar to A16.
Because the zombies would attack from any angle and mostly not get any block attack boni working the most problematic result would be that the box with spikes would be here again as the only and most effective way by far to combat these zombies
If they were directly at the target's position but couldn't get to the target because it was higher up, they didn't know what to do. That's why you could direct the zombies wonderfully from above and e.g. pull them through spikes like a magnet. Now the destruction mode has been introduced. If they can not reach you then they destroy blocks nearby.
It isn't as if defending from a higher position is impossible now (it probably was in 17.0 where the block damage bonus for multiple zombies was very high). You just can't do it anymore with filigrane stilts. You need to put yourself on a durable foundation. Leading ineffective zombies around and laughing like a maniac was fun but also too effective for the effort you put into it. Aka an exploit.
That's why I have plan A which works so well that all 3 waves of the zombies are destroyed long before the night is over. And that with a gamestage of over 500.
Boasting about taking on the horde and "destroying" it completely and then having a plan B of meekly driving off on a minibike is sending a mixed message :cocksure: . That was my point.
Building bases in creative mode and testing them before really using them is your way of eliminating risk. If I did that I would need no plan B either. I try to keep risk low by building robust bases that should work even if zombie AI changes, and I make a plan B that should work even if luck is against me.