Here are my ideas for the 3-Death-Streak perks.
Losers Always Win: This perk grants you the same effect of 7 kill streak.
This Guy Is A Fag: Instantly kill the target of your choice.
I wished This Game Was Like Section 8: Get lock-ons on enemies. (Temporary aimbots)
Winners Go Blind: This perk will spawn a flash, then stun in front of all your enemies.
F*ck your boards: This perk will remove 100 points on the opposite team for every 3 deaths streak.
Bullsh*tes R' Us: This perk will give you an instant-explosion martyrdom for the whole match every time you die.
Sick Of This Game: Grants you 200% for every attribute. Perfect with LMG's!! (Speed, Damage, Health regen, ETC)
Just Like Pigeons: Release a regular martyrdom on every players of the opposite team.
I'm More Used To CS:S/Halo: Removes sights, now every shot you make should be as accurate.