Well, i tested it and i have some suggestions:
First of all, in my opinion this should be developped as a "mutation" or a new gamemode instead of changing some things in a pre-existent gamemode. If you can't, this plugin should be defenitively developped on a COOP gamemode (possible with infectedbots) not versus (the purpose of this gamemode is to survive as much as possible, right? So why should we need scores, and have to play the same map twice?).
Said that, i think it's better to start with all humans survivors and without special infected (neither humans, neither bots). Tanks and Witches should spawn regularly.
Defibrillators should be replaced with pills or adrenaline, also you should replace medkits (so the bleeding can also be interpreted like the infection spread, and the only treatment to it is to slow it with pills and adrenaline
). You should also decrease the min and max time spawn of mobs by a half (maybe create a convar) and increase the population of zombies by a half (here also you can create a convar). I think this is enough to balance the game. If not you can create another convar to reduce by half the "non headshot" damage done to zombies.
Time convar should reduce by a half theese commands:
z_mob_spawn_max_interval_easy (Default: 240)
z_mob_spawn_max_interval_normal (Default: 180)
z_mob_spawn_max_interval_hard (Default: 180)
z_mob_spawn_max_interval_impossible (Default: 180)
z_mob_spawn_min_interval_easy (Default: 120)
z_mob_spawn_max_interval_normal (Default: 90)
z_mob_spawn_max_interval_hard (Default: 90)
z_mob_spawn_max_interval_Impossible (Default: 90)
z_mega_mob_spawn_max_interval (Default: 900)
z_mega_mob_spawn_min_interval (Default: 420)
Zombies population convar should increase by a half theese command:
z_common_limit (Default: 30)
z_mega_mob_size (Default: 50)
z_mob_spawn_max_size (Default: 30)
z_mob_spawn_min_size (Default: 10)
Zombies resistance convar should reduce by a half theese commands:
z_non_head_damage_factor_easy (Default: 2)
z_non_head_damage_factor_normal (Default: 1)
z_non_head_damage_factor_hard (Default: 0.75)
Now that the game is balanced (i tested it 3 times with theese settings on normal difficulty with some friends, and the first always died on the second-third map causing the end of the game during the fourth map) there are some problems during the "transformation":
1)Sometimes, when someone die, 1 player will get 63000 (something similar) of hp... Don't know why...
2)As you writed, 1 friend got stucked with his tank, and he couldn't do nothing (neither write in chat).
3)As a result of point 2, i try to use the swap command (of the "score team manager") to send him to the survivors' team, but everytime i try to swap him again to the infected's team his survivor (that he was controlling) die and he take control of another survivor bot.
4)I don't know if this happens also in other map, but i found that in the second map of dead center, when we close the door of the saferoom, the game didnt' continue... like if someone isn't in the saferoom.
We though that maybe the plugin didn't count the dead bots transformed in infected as dead... (after further check, i discovered that the dead bots just respawn in the initial saferoom, and try to redo all the path on their own.
5)When i'm playing online, seems that killed (and kicked) survivors will just respawn in the next saferoom... Like they were just killed normally. I suppose this shouldn't happen right? Once dead, they should stay dead until the campaign is over, i think. Or this isn't already included in the plugin?
6)I use Infectedbots plugin, and during my test i initially changed the "infectedbots_max_specials" (how many special infected, either bot either human, every 25 seconds) to 0, and i always raised it by 1 everytime 1 survivor died, can you make it that it automatically add 1 bot to the infected side when a survivor bot die? This may be usefull as players may leave the game during a session, and the new "survivor-bot" once dead don't switch to the infected side, avoiding so the "transformation"
Ok, that's all! Oh yes, i don't know if you liked all theese suggestions, maybe i'm invasive, but i told all this think because this plugin can raise the top if well developped! Your idea is awesome!
I don't know if some of this suggestions (like the replacements, or the convars) are really hard to do because i'm not a programmer
so i can't help you very much, but if you want i will test all your updates and i can share you all my tips!
Oh, about tips: Until now when all survivors are turned, the game just restart that map that's a little useless, why don't make it that when the last one die, the end credits appear? (for end credits i mean the black screen with "In memory of: ...." that one that appear after finishing the campaign) And then you can make the players vote to restart the campaign (like a rematch in versus) or return to lobby!
Or maybe this is too hard to do?
I don't know, if possible it would be great! Let me know what do you think!
P.S: Sorry for my english.