Hello! Without further ado, let's get started on the Suggestions.
Firstly, a simple yet fun killstreak system, like in Call of Duty MW1.
It would work like this:
To unlock killstreaks you need a total score of 10 or more, so you don't jump right in the game and just get streaks.
At 3 kills you would get something like a radar. That could either be a radar that would mark the enemies near you or on the whole map. To not make it overpowered, I'd say that it could only reveal enemies that are in the open sky, although that would create some problems with fully covered maps.
At 6 kills you'd get an instant refill of blocks, health, grenades and ammo wherever you are on the map.
At 10 kills you'd get to call an airstrike on any square of the map. That would either be dropping grenades like in the mod or just a big bomb that would kill everything that stays in the open sky.
Killstreaks should be wiped on death and when a 10 killstreak happens the person who gets it should begin a new 3-6-10 cycle of killstreak. For each called killstreak, the player who called them should be awarded a small number of points. Killstreaks should not stack (so if I call in an airstrike that gets me 3 kills I wouldn't get a radar / UAV).If a player dies with an unused killstreak he can use it in his next life. If a player gets 2 radars from previous lives they should stack and he should be able to call in 2.
Feel free to add and improve on my suggestion and also contribute with your own suggestions. Thank you for reading.