If I could deal with the iron sights I'd like your setup quite a bit. The last couple of days I've been rocking the FAL, and it's been going well. Pretty much sticking with my standard assault rifle class with it, holo sight (for the improved damage, not because I like it better than RDS), silencer, semtex, raffica silenced/RDS, bling (duh), stopping power, and sitrep.
The FAL was completely useless for me on Xbox, but on PC it's a complete beast. It's pretty easy to put two shots on someone, and that's all you need. I have the occasional embarrassing failure at close range but for the most part I've been doing really well with it.
Even got a nuke today on Wasteland in a free-for-all. Chopper gunner got me from kill 11 to kill 25... but my harrier got zero kills and someone shot it down. I saw chaff once from my apache, which means someone must've been firing something.. but I guess I managed to keep shooting that guy before he got another shot off, or something. I got to killstreak 25 at kill #27... and then I just stopped firing the chopper gunner in case I accidentally killed extra dudes sitting around with cold-blooded or something. After not getting to use last nuke I couldn't let that happen. Final score 33-3.
The kill that got me my useless harrier was pretty funny. I was fighting outside of that little shack. Sitrep told me there was a claymore in there by one of the doors... but I kept running into people while trying to figure out how I wanted to deal with it. Finally I got a moment and I went for the bullet penetration to explode it. To my surprise I got the 'you hit somebody cursor' and spammed another 6-7 shots through to get the kill. I have no idea what that guy was doing but he must've been camping there for 2 or 3 minutes with my raging firefight outside never so much as willing to take a peak. All that camping to be unceremoniously dropped like that
You mentioned switching your ACR class to stealth mode as soon as a UAV shows up. I've starded just shooting UAVs down with the FAL.... takes less than a magazine with stopping power pro.
Oh, one of the main benefits of the FAL that I was looking to mention... with the silencer it's pretty quiet. If you're picking off someone at medium range, it takes two shots that make very little noise. It's not very jarring. Whereas FAMAS or M16, even with the silencer, those three shot bursts seem to draw a lot more attention. I don't really remember how well that went wit the ACR back when I used it silenced. The thing is it takes like 5 shots to the chest to bring someone down... so it seems like more exposure than I'd like.
After getting the nuke I went to a care package heavy killstreak setup. I think it's care package, air strike, and emergency air drop. Since the care package won't add to your killstreak regardless. And the airstrike is mostly just for fun, sometimes it doesn't get anyone, if I aim well I might get 2-3, but it's not really reliable, it makes my frame of mind a little different. I'm not so concerned about using the stuff as soon as I get it to chain together the kill streaks. I stick with the shooting, and then when it's safe I'll toss whatever air drop markers I have and hope for the best. This newfound patience led me to discover a handy trick. When I get a chopper gunner or an AC130 out of a care package, I no longer crack open the laptop like a kid tearing the wrapping off a Christmas present... I tell the game that I would like my Danger Close tubing class, and go out in a blaze of glory. Then when I have my danger close on, it's time for the AC130. I can't believe I didn't think of doing this before, I guess it's probably since I'm usually trying to use the 11 kill rewards as a springboard to a nuke. But man does danger close make that stuff so much more deadly. You can drop those explosive rounds into lots of doors and openings to kill the hiding bastards. Yeah, there are still some maps that are...poor... for chopper gunner or AC130, but it's still a big help. I seem to get the 11 kill streaks out of care packages decently frequently. Yeah, it's usually just a UAV or something, but I get a lot more 4 kill streaks than I do 11. And the emergency airdrop at 8 still isn't too bad to get to. My last care package/EAD double feature gave me a Predator, a Chopper Gunner, a Pave Low, and two Sentry Guns. The Sentry Guns landed outside the fence because it's annoying to line up the EAD... but even with that portion squandered that's a pretty good haul for 8 kills.
The FAL was completely useless for me on Xbox, but on PC it's a complete beast. It's pretty easy to put two shots on someone, and that's all you need. I have the occasional embarrassing failure at close range but for the most part I've been doing really well with it.
Even got a nuke today on Wasteland in a free-for-all. Chopper gunner got me from kill 11 to kill 25... but my harrier got zero kills and someone shot it down. I saw chaff once from my apache, which means someone must've been firing something.. but I guess I managed to keep shooting that guy before he got another shot off, or something. I got to killstreak 25 at kill #27... and then I just stopped firing the chopper gunner in case I accidentally killed extra dudes sitting around with cold-blooded or something. After not getting to use last nuke I couldn't let that happen. Final score 33-3.
The kill that got me my useless harrier was pretty funny. I was fighting outside of that little shack. Sitrep told me there was a claymore in there by one of the doors... but I kept running into people while trying to figure out how I wanted to deal with it. Finally I got a moment and I went for the bullet penetration to explode it. To my surprise I got the 'you hit somebody cursor' and spammed another 6-7 shots through to get the kill. I have no idea what that guy was doing but he must've been camping there for 2 or 3 minutes with my raging firefight outside never so much as willing to take a peak. All that camping to be unceremoniously dropped like that

You mentioned switching your ACR class to stealth mode as soon as a UAV shows up. I've starded just shooting UAVs down with the FAL.... takes less than a magazine with stopping power pro.
Oh, one of the main benefits of the FAL that I was looking to mention... with the silencer it's pretty quiet. If you're picking off someone at medium range, it takes two shots that make very little noise. It's not very jarring. Whereas FAMAS or M16, even with the silencer, those three shot bursts seem to draw a lot more attention. I don't really remember how well that went wit the ACR back when I used it silenced. The thing is it takes like 5 shots to the chest to bring someone down... so it seems like more exposure than I'd like.
After getting the nuke I went to a care package heavy killstreak setup. I think it's care package, air strike, and emergency air drop. Since the care package won't add to your killstreak regardless. And the airstrike is mostly just for fun, sometimes it doesn't get anyone, if I aim well I might get 2-3, but it's not really reliable, it makes my frame of mind a little different. I'm not so concerned about using the stuff as soon as I get it to chain together the kill streaks. I stick with the shooting, and then when it's safe I'll toss whatever air drop markers I have and hope for the best. This newfound patience led me to discover a handy trick. When I get a chopper gunner or an AC130 out of a care package, I no longer crack open the laptop like a kid tearing the wrapping off a Christmas present... I tell the game that I would like my Danger Close tubing class, and go out in a blaze of glory. Then when I have my danger close on, it's time for the AC130. I can't believe I didn't think of doing this before, I guess it's probably since I'm usually trying to use the 11 kill rewards as a springboard to a nuke. But man does danger close make that stuff so much more deadly. You can drop those explosive rounds into lots of doors and openings to kill the hiding bastards. Yeah, there are still some maps that are...poor... for chopper gunner or AC130, but it's still a big help. I seem to get the 11 kill streaks out of care packages decently frequently. Yeah, it's usually just a UAV or something, but I get a lot more 4 kill streaks than I do 11. And the emergency airdrop at 8 still isn't too bad to get to. My last care package/EAD double feature gave me a Predator, a Chopper Gunner, a Pave Low, and two Sentry Guns. The Sentry Guns landed outside the fence because it's annoying to line up the EAD... but even with that portion squandered that's a pretty good haul for 8 kills.