I've used the iron sights. They're fine, but I prefer the slight magnification I get from the holo-sight for getting kills at extreme range (I can't tell you the number of "Longshot!" bonuses I've gotten with this build). I have another build that's like the one I posted but with Heartbeat Sensor/FMJ that I use for exactly that, sweeping out campers.
My main RPD and perk setup is fine for what I use it most for (capturing points, blitzing between areas, and some light camping), heck I've earned over 600 kills with it, it's my secondary weapon that I'm feeling needs adjustment for the occasional points where I come up behind a small group of snipers (like typically happens in Highrise), or capturing a point in Domination where I don't want my blasting the defenders to give me away while I hold the point. Being completely silent and virtually undetectable until I open fire is all the advantage I need when I get the jump on a pack of opponents, I can cut 2-4 targets to ribbons easy enough, I just have to move out afterward. Stopping Power just isn't worth the protection I'd be giving up with Cold-blooded Pro.
I'm loving Last Stand too, but the rare time I've gone into it and haven't gotten quickly killed by my would-be killers teammates, I've actually waited it out and stood back up. Why take a death if you don't need to?