1. Issue: In realism-based tactical first-person shooters such as Ground Branch, I personally prefer modes in which the players are only given one single life as it encourages us to adopt a particular mindset (and by effect, develop certain styles of play) that complements the theme and mechanics of the game well. However, I cannot deny that the respawn system does have its own merits, even in Ground Branch.
I agree with th33f: let's leave it to the server admins to decide the intensity of the games that they want to host. If a respawning system is to be implemented in a gamemode, then there must be an option to adjust the number of lives allowed per player, from 1 to infinite.
If a player dies in a non-respawn large coop game, he would have to wait longer before he could play again, which might cause him to get bored, lose patience, then quit. On the other hand, if a respawn system is introduced, this might encourage players to play recklessly.
We should maintain a time delay after each death to act as a penalty (a "respawn delay penalty").
This should encourage players to be careful with each life regardless of how many lives are allocated per player.
All dead players return to the Ready Room, where they can run around, respec their gear, spectate and stuff.
This definitely beats the boredom of not being able to do anything while waiting for the respawn timer.
The initial duration of the respawn delay penalty should be inversely proportionate to the number of players playing.
Therefore the larger the number of players, the shorter the duration of time before one could respawn as reinforcement.
For the purpose of illustration, I will assume that the maximum number of players allowed on a coop server is 8 so that I can use the least common multiple of 840 as a constant. Therefore in a 2 player game, we could set the initial respawn delay penalty to 840/2 = 420 seconds (i.e. 7 minutes). For a 7 player game, the initial respawn delay penalty would then be 840/7 = 120 seconds (i.e. 2 minutes).
Subsequent deaths should be penalized with a longer time delay.
Therefore even though the number of respawn is set to infinite, the consequences of repeated deaths will be exponential in severity. As Jonathan puts it: "All the more reason for you to be more careful next time you play".
Using the above example, we could for instance double the duration of penalty per subsequent death so that although in a 7 player game, the first time a particular player dies, he will only be penalized with a respawn delay penalty of 2 minutes, but on his second death, the penalty will be 4 minutes, his 3rd death 8 minutes, and so on.
3. Issue: In a non-respawn large coop game, a dead player needs to wait for the remaining players to die in order to play again. Therefore the sooner the rest of his team dies, the sooner he gets to play again. In my opinion, this in in contradiction to the spirit of the game, where dead players are supposed to root for the remaining players to survive and hope that they will succeed in completing the mission (or else they would have "died for nothing" LOL).
Suggestion: Players will only respawn if all the following criteria are fulfilled:
All dead players (that still have lives allocated to them) have voted "Ready" on the monitor.
The respawn delay penalties of everyone in the Ready Room (that still have lives allocated to them) is up.
Therefore if a player is dead, then the dead player would want the other players on his team to stay alive so that as soon as his respawn delay penalty is up, he could respawn immediately as reinforcement. Because if another player dies, then -- depending on that newly-dead player's duration of respawn delay penalty -- he may have to wait longer for the newly-dead player's respawn delay penalty to be up before they could respawn together.
This also makes reinforcements to respawn in waves, which, as fatmarrow has implied (and I agree), will encourage teamwork and more strategic play.