Zombicide taught me that, despite zombies not really being my thing, zombies can be fun. It has elegant rules which stay out of the way and keep the players focused on the game. (Note that "it" specifically refers to "Classic" Zombicide, not later renditions like Black Plague or Invasion, neither of which i've played.)
Many players actively bemoan Zombicide's rule which says that if you shoot a gun into a crowd which contains both zombies and other Survivors, you will, with absolute certainty, hit the (former) Survivors first. The 2nd Edition unfortunately changes that rule, not because it was broken, but because they caved to whining players. Consider...
If your buddy knows that he "might" hit you when firing into a group of zombies, he's more than likely to take the shot. If he knows that he will definitely hit you, he's not going to take the shot unless doing so is of major strategic importance. (Sometimes we simply have to take one for the team to ensure victory.)
The "hitting survivors first" rule, which seems to pain most players when they first start playing the game, was a largely-unrecognized stroke of genius on the designer's part, as it eliminates the problem of your ostensibly coop buddy taking that shot only because he "might" miss you and hit the zombies instead.
Remove that rule and you've removed an important chunk of the coop aspect of the game, converting it to semi-coop.
That said: the first time i read that rule i thought, "well that's stupid!" but i always play games as written before attempting to modify them because practice has shown that the designers often know their games better than i do. The hit-Survivors-first rule is not only not that onerous in practice, but it also leads to making interesting tactical decisions. Removing it from the 2nd Edition was, in my oh-so-humble opinion, a mistake.
That said... Once the designers committed to the 2E change that loss of a single party member always means immediate loss of a mission, they had to include this targeting priority change to give players a last-ditch way to try to free colleagues trapped by zombies. The "we all lose if one of us dies" rules change also means that nobody will be casually betting on whether or not they're going to hit another player's character while shooting at zombies. So, in the end, it works out. i'm still annoyed by them caving to whining players, though, simply on principle.
GET OFF MY LAWN!