Good point, instead of a revive if you're bit you should be wasted by one of your AI buddies and either have to start again or take over as the AI guy that wasted you. There is no cure for a Zombie bite, only immediate removal of a limb and I doubt anyone would want to play on crutches for the rest of the game.
Are they still planning second half of 2018? Probably not the best move IMO. Between annual franchises and RDR2, who the hell is really going to put this at the top of their list?