Stealth Bomber and EMP are not OP (and no, I'm not a user either. I also use Assault or Specialist).
Stealth Bomber seems OP because people just either stay clustered together, aren't near cover, or something that makes them more easy targets, but getting kills is also not the Stealth Bomber's primary use. If it does get kills (0-2 on average from what I see outside of named reasons, in which case, that's that team's fault, not the Stealth Bomber's), good for the user, but it does what it's supposed to do; clear a path towards a location, usually an objective, either by killing people or, much more likely, getting them get out of your team's way in that path. This is followed up by the more severe concussion effects of being near the explosions, thus allowing your team to get kills while they're vulnerable, so the Stealth Bomber is supporting your team and not used solely for getting you kills.
EMP supports the team by knocking out killstreak threats if there's a number of them and by making the enemy players more vulnerable by making their vision all fuzzy, and preventing them from throwing up new killstreaks. And considering it's still an 18 point Killstreak, I'd say it's pretty fair overall, Support or otherwise.
Both also seem OP because it's not "bad" players getting them "easily", but it's actually more better players simply taking advantage of how Support works because now they don't have to worry about losing their killstreak after being picked off by a random/"lucky" noob/camper/etc when they're just 1 off. Now they can get 1 off, die, and STILL just need 1 more to get it. Those types of players usually have the Stealth Bomber, EMP, and Escort Airdrop as their 3 Support Killstreaks for that reason.
But if one wants to still keep going as dgaray67 points out, what about the Care Package?
Sure you COULD get a mere UAV, but the chances are actually quite high overall that you'll be getting something pretty good. A majority of the time, from my experience, I or the enemy team using one, the contents tend to usually be a 9+ point Killstreak (the whole 1% or 2% charts are pretty bogus overall). How exactly is that "fair" to Support users who still have to at least get their higher number of kills when Assault users like me and others can simply bypass so many with just 4 kills (3 with Hardline)? 3 kills resulting in a Pave Low/AC-130/AH-6/Reaper/etc? Even something like a free Sentry Gun or Assault Drone that we don't even have to have delivered like normal, but simply deployed on the spot?
