I'll keep saying this in every rejoin suggestion, that is focussing on only one gamemode: If this gets implemented, this shouldn't be just for eggwars and you should still be able to rejoin once your egg is broken. Simply by killing the player if he/she leaves. If you leave, lag or just accidentally leave the server, you get killed. If you rejoin when your egg is alive, you obviously died, so you'll respawn with nothing but your kit. If you rejoin when your egg has been broken or your eggs got broken when you left, you rejoin as a spectator. If you rejoin in Mineware you'll keep your points but you probably missed out on a few points. If you respawn when a microgame is going on, you automatically lose that microgame. Respawning in Tower Defence won't change anything. Since you can't die. If you respawn in Skywars, Lucky Islands, etc. you'll rejoin as a spectator. Quick note: Even if you're not in combat, you'll die.
But, i would bee too op for another games and even for eggwars. Because thats a way to be able to spectate a game. And this ofc will be broken if you are in a party, because a friend can tell if the enemy haves X items, Covered the egg etc.
I mean yeah, when you die in normal eggwars without your egg you spectate, but its unfair to rejoin again to only spectate that can give a advantage like, oh i am going to leave, and then your friends says you to rejoin to help him to find a hidden guy.
Also, it would cause bugs becuase if you join in a game but you leave (cause of lag) BUT, the past game its still running, then ? who the rejoin thingy will choice?.