Zombies are to intelligent and fast.

[pixl (DayZ) 0]

climbing a ladder to get away from a horde of zombies chasing me, once i was at the top i didn't even think to check twice if they were still following me because i thought zombies would be stupid. a few second later there were about 10 zombies on the roof, mauling me to death.

zombies should not be able to climb ladders.

[Mags (DayZ) 0]

I want to elaborate on what Solid.nl posted and this thread seems to be the best place for this suggestion.

Problem: Cost/benefit is too great to fire your weapon (non-silent). Again, once alerted, the danger escalates exponentially.

Firing your weapon attracts WAY too many zombies.

Suggestion: reduce sound proximity, reduce zombie count, implement melee (Arma3 supposedly), increase silent weapons (less realistic but still an option).

I do think this issue needs to be examined more closely. I also think its a real problem in this patch.

[Land Squid 22]

Something that I'm not sure the devs are aware of yet, but I hope gets taken into consideration when they look at tweaking the AI: Currently the zeds run away from frags just like they're still the old Arma II AI. My group was stuck up on a hospital surrounded by about 30 of them so we thought to try tossing down a smoke grenade to concentrate them (worked) and then tossing a frag into their midst to thin the herd. The moment the frag hit the ground they scattered like cockroaches even though the smoke was still burning.

[B00tsy (DayZ) 19]

Maybe we could have an option to 'play dead' 2 times per live. If you have 30 zombies going after you can try to play dead and the zombies will stop engaging you and run past you. That could be an approach to solve the overkill issue and that also fits the gamestyle and scenario.