Problem is, 2 kills with Hardline. Could quite easily get 5+ a game without playing very well, if another player does the same thats 10 RCXD's in one game. Thankfully doesnt happen every game and I am getting better at dodging them.
But its a balance thing, that person is getting 2 kills then calling in an RCXD, which will get them about 3 kills at most, but the majority of times just 1 then dieing and repeating the process, whilst someone isn't dieing but gets up to a higher killstreak like a chopper gunner or gunship then they will rack up a lot more kills with that.
RCXD can be very handy plus it keeps Faded happy
I do agree however it's incredibly annoying to keep getting killed by the damn things.
Let's not forget the spin I made you do which resulted in Danny getting killed by your grenade

And the whole death by killstreak stat would be the same on MW2 with the Predator had the kill rewards not added to killstreaks.