I play firefight quite a bit and have come to the conclusion that what firefight really needs is Killstreak rewards like call of duty MP.
For example
25 kills w/o dying= 1 weapon drop near your location
50 kill= warthog delivered by pelican
75 kills= 6 man marine squad
100 kills= Falcon gunship overhead for 2 minutes
150 kills= scorpion delivered by pelican
Killionaire= overshields
etc.
What does everyone think?