You missed one trait of the current Support streaks.
With the current system, you can't do a "short" chain that holds three rewards. You can do a single 4, two with a 4/5, but the minimum to get three is 4/5/8.
You offered a 4/5/6 streak. If you don't want CUAV, you can get a current 4/5/8 package for 4/5/6 in your new set. It might not seem like much of a difference, but consider that if you get 24 points in a match, then you can complete a 4/5/6 set four times, while you can only complete a 4/5/8 set three times.
One other possible concern is that the current system overlaps three 18 point streaks. Bumping the EMP to a higher cost makes it take slightly longer to obtain, but also means someone can take either Escort or Juggernaut and still take EMP as well.
The point of the increase of the EMP would be to reduce how many are gained being that you would need 44 points to get 2 compaired to 36 making it harder to chain emp ect as for being able to get Jugg/air i personaly consider both these to be nowhere near as good as EMP the jugg can be killed (somtimes in as little as 5 seconds) can be stolen, the air drop can be shot down without even droping any thing and every thing it does drop can be stolen the EMP on the other hand can't be stopped (unless another EMP is doing so) destroys all killstreaks in play and then block any further killstreaks for a whole minute the increase of points needed to get it reflects that also for the lower chainswhile i understand the point.