why? do you really think 1 kill is going to be that much of a difference? people are still going to complain about it regardless. not trying to be an ***, just trying to explain the stupid mentality of most of the people who play this game.
RC-XD would harder to achieve if it requires more than 3 kills, that's for sure. If it's harder to get... a lot of people may not be able to get them.
As it is now, the fact that they are commonly used in any payload plus it being a cheap way to get kills for those without flak jacket, bumping up the kills to achieve the RC-XD may have a few players thinking twice and question the value of the killstreak.
Same goes with other killstreaks as well, for example, can you imagine if dogs were 3 kills instead of 11... you know how insane that would be? And people would be definitely be complaining about it.
Unfortunately, the problem that would arise is if the next installment in Treyarch's game has to require more killstreak for RC-XD. People won't accept that either...especially if it does the same amount of damage, but Treyarch was wise to set this particular killstreak so low; so that everyone can get their try at it.
Better to stick with low killstreak numbers, that's easily achievable to everyone, not just for the gifted players.