Previously the zombies used to just wander around looking for brains then chasing them down relentlessly. I personally prefered this method because it meant that I did not know where about the zombies were. There could quite easily be one right around the next corner or some where I thought was a safe spot that one hand found it's way into.
Now the zombies follow a specific path going between various nodes. Whilst this does ensure that the zombies will go where they are meant to it also makes them a lot more predictable and easier to prepare for.
I understand that the new method is better suited for larger maps but it does have it's flaws (IMO).
Originally you could be hanging round for them for ages for one or the whole hoard could appear from all directions unexpectedly, now you can predict exactly where they'll come from and just line up your gun and shoot, even when they are nowhere in sight. We also have the problem with zombies standing still the moment their path is blocked, they used to continue wandering which meant that those of us who enjoyed chasing them down instead of hiding behind barricades could enjoy the hunt.
I'd like to hear everyone else's opinion on which method they preferred. If people prefer the old method I hope DC would enable a server setting to toggle between them. If I'm the only one I'll just keep switching back to the previous version when I play off-line.