No. The game doesnt work without the timer. You cant just rip it out, the entire campaign and every single quest revolves around things changing around you based on time of day. if you want to play a game to mow down zombies play the hundreds of other zombie games out there.
It's like saying you'll play majoras mask without the day system. It's completely moronic.
They could have a 24 hour cycle that repeats without a hard timer for the game. Plenty of games do that.