My Ender's Game inspired game type
Each match starts as a free for all, each kill re-spawns the victim as an ally to the player building kill based teams. Ally means no friendly fire, support & command perks shared and a shared kill based team building. As a player makes kills they permanently earn command abilities and/or unlock weapons which can be allocated/shared to/with team members thus escalating combat.
A leader is the player that sits above others in a hierarchy. If a leader is killed, the kills they have earned disband (no longer allies) into their own earned kill teams (*or re-organized hierarchy) and the leader re-spawns near their killer as an ally in the new team hierarchy. Unification is the win condition, however this isn't the end of the match.
To really cut and polish this gem, take this unified army of players and face them against overwhelming waves of unfriendly [insert favorite monster/enemy to carry out genocidal warfare upon]. Two rewards, the first is for the rank a player earns based on kill streaks indicating unification personally earned. The second is survival time achieved during the survival mode, this is a shared reward.
*For example: You join the game you make a few kills which unlocks the ability to target enemies for allies to focus on, a close range radius passive healing ability as well as unlocking a heavy suppression weapon. Which you hand off to a newb you owned right away and has been following you to take advantage of your healing ability. You notice a fairly large team forming and try and sus-out the leader. By targeting but not killing the enemy the hierarchy starts to be displayed as a rank icons over top of a targeted enemy. Your small team grows as your team makes kills and you target and kill the leader of the other group disbanding the group. You pull back and let the disbanded teams fight it out, taking pot shots at the leaders that are growing their group faster. Your flank is overwhelmed by a group you hadn't been scouting and you're killed. All that work for not!!!? Starting off as a grunt under some other jerk is pretty frustrating however all the perks and weapons you unlocked are still available and your new commander recognizes that, he re-organizes a few teams of soldiers as your subordinates (they aren't thrilled), you drop some rad weaponry and perks into their hands and everyone is happy. You take your team and you go after your old team members, rebuilding your old empire. This time, with the added support perks of your new commander. Unification is achieved and you earned the "re-organized second in command achievement"! A count down. The commander is organizing everyone into a fairly tight parameter on a plateau and your teams protects a few key choke points. Everyone is gunning for a new survival time record to make the leader board for the day. The Shakespearean tragic ending creates lasting bonds of friendship between players and unending peaces on Earth for all humanity (with high speed internet;).
Hope that little read made some of the ideas more clear. This design can be scaled which is nice and elite players have to evolve their play to survive command gameplay, instead of just dominating combat matches, meaning less match making. Other fun additions could include none combat foliage painter, where players discard their weapon (and ability to fight) and choose to run and hide. Their character acts as a paint brush, slowly painting forest all around them to hide in wherever they go on the map, perhaps earning "titan" physical abilities to move through the forest (altering the end game).
I've posted this design before but here it is again. Feedback of all kinds is always appreciated. I'm a hobbyist character animator, give me a shout if I can help.