Going along with what Cyber was saying, bhopping (binding "Jump" to a button) is a skill that indeed takes some practice to perfect, and is a deserving advantage for those people that take the time to master it (imo). I myself played the occasional bhop server, but really I think surf maps were very helpful too (used to be what zm is to me now). Being able to get a feel for the terrain, plan out your jumps, gauging distances, and being able to actually evade human's shots is not a simple matter of "Just bind your jump to mswheeldown".
When humans lose on the ZMod server during an escape map, 99% of the time it's because most if not all humans are looking forward paying no mind to the zombies behind. In that instance, OF COURSE zombies are going to win. You can't expect IBIS server to create zombies that won't eventually overtake humans. It's the humans' objective to not only get to the end, but to SURVIVE (meaning nading, shooting, knifing those damn zombies back to the hell from which they crawled out of!). Many people have already said this, but shooting zombies (any class) in the head will indeed slow them down if not stop them dead. Deformed class can be a bit difficult now with that extra speed boost (hence why I'm usually playing it) to stop, but I assure you head-shots do stop me.
As for crouch spots, I do feel that there is some controversy here... I've noticed that zombies (fast and predator especially) are able to hide their hitboxes in the ceiling when jumping in crouch spots, which makes them quite annoying when you're a 1-3 human group. Of course when you get to 8+ humans you'll be fine, but I get claustrophobic at that point and end up just leaving the cade anyway... I'm not THAT friendly >.>. This was addressed in another forum a while back (http://www.ibisgaming.com/forums/sho...t=Crouch+spots) where I was questioning a player for scripting or just jumping. Although it was not scripts, a few of us discussed the possibility of changing physics to account for the missing hit-box for the head, and it would just be a mess of code probably =\. Long story short, you as a player need to find your own way to cope with this disadvantage, meaning either bring a powerful PARA with you, or stick with people you trust.
So yeah... until the rules change, bhopping is fine so long as you aren't using a script (don't even try one cus we WILL know, we WILL ban you for a month, and you will finally end up PERMA-BANNNED after you go through our "justice system" at IBIS).