The cooldown code hasn't changed, and with delay being 0 it will honour the director (so if your ghost spawn min/max's are 15/20, it will take that long before being available again - but sometimes the director lowers that value to something like 5 secs if there's not many in play). If you show the hud and stay as a ghost and let some of your players die do you see the (C) cooldown symbol for that infected? and you're able to change to it? while you see it? (assuming you're playing a 4v4 game with limits set to 1). You could also enable zcs_debug and see if it's showing class is cooling down/not able to select while class is cooling down/class released.
sm_cvar or just using the cvar does return the values for me, in console. Also using sm_cvar from client console returns the values also. You trying something like rcon zcs_enable ? or rcon sm_cvar zcs_enable ? As they work for me also.
ne0chaos,
Yes that could be possible (I prefer no cooldown either =) .. I'll note it for something in future.