I'm with you - the lack of support streaks is extremely annoying in this game. I thought they were an ingenious idea as they helped out players like me, who have god-awful K/D ratios, without giving us too much of a boost. I could contribute to the team more with support streaks than I ever can with standard kill streaks.
They're a brilliant idea. What you think players doing well should get an extra boost to their kills? Or in Mario Kart players in lead should get infinite boosts?
Support streaks where an awful idea. Players shouldn't be rewarded when they're playing badly. Mario Kart, take note.
MW3 was decent since you had the support streak so weaker players could still rack up killstreaks without worrying about dying so they moved more.