by StormKnight
Now admittedly, I don't think the rule as written is a design flaw, and calling it so, beuuase you don't like it, is a bit hyperbole.
Any "design flaw" is going to be subjective. Somewhere, there are plenty of people that think money on Free Parking is a wonderful idea. It gets pretty silly if we have to preface every statement about rules with "Well, someone could like this, but I personally don't." If you think it's a flaw, say it's a flaw and be done with it.
To me, a game like Zombicide is meant to be a, well, thematic game. It's supposed to create the illusion that you're guiding a character fighting zombies.
In a perfectly thematic game, a player who had no idea what the rules of the game are could imagine their actions based on the theme, narrate their actions to a "translator" player, and have those actions carried out in the game with perfect accuracy. (That's basically what an RPG is).
A boardgame can't have that, but the further the rules take you from that clarity from imagination to game, the less thematic the game becomes.
Rules like the "running out zombies" and the "zombies split into two" take you further and further away from the theme. They break the illusion. You aren't fighting zombies; you are fighting arbitrary game mechanics.