I remember playing zombie plague 4.3 on 2009 - 2010. That was the golden era of zombie plague. There are a lot of server has their own unique addons and plugins. I do also remember how dark the map was and how hard it is to get ammo packs. I could spent hours on that server, because the main goal is to survive and collect ammo packs to buy in-game items. Man, that was fun.
10 years later, I downloaded CS 1.6 again just to play zombie plague 4.3, but none of the existed server have similar feature to the server I used to play. My opinion is, there won't be more new players just to play CS 1.6/ Zombie Plague 4.3, people who play CS 1.6 are the people who want to experience the good old days they used to have when they play CS 1.6. So, keep the server original like it used to be, I'm sure there will be more old player will play on this server.
The fact that some of you spent 1.4k hours every single day just to play on this server is scary. What are you doing with your life? Go spend your time with your family or do some of your favorite hobbies, don't waste your time.