Yeah, the Shark only has laser warning, and I hear its really only for strong lasers, like ranging. Beam riders may not be strong enough to light it up. Heli's were not made to go up against the better SAMs. You need to hug the earth, and ambush them from cover. Do a popup attack just at the edge of a hill, so you can scurry back behind it if you see a launch. Also remember, the vhikers are fast missiles, so if the missile is SARH, you might be able to kill the tracker before the missile can hit you. In that case, after the tracking radar is destroyed, you can just move out of the path of the missile. If its one of the larger missiles (like SA-11), get FAR out of the way, as if it detonates from proximity detection, the fragmentation field will be quite large and take you out.
For the IR's, you should be able to take them out somewhat safely from the maximum range of the vhiker. I think the Avenger (IIR) has something like a 10km range? Ambush it and shoot before it can detect you. Just be sure to have nearby cover available.
For manpads, they don't seem to shoot until your about 3km away. Not sure if that is realistic or not. Probably has to do with no detection except their normal vision. Just remember, from what I've read and seen in the sim, the modern IIR's seem to be very flare resistant.
A-10C's pretty near the same IMO. Anti-Sam was really made for F-15, etc. with HARM missiles for maximum survivability. Best bet is too send in a SEAD flight ahead of you, if its available.
I also agree, the Shark seems to be a little underequiped when it comes to missile detection and defense. While some things are new and nice, others seem down right primitive. Ironically, I think the best SAM in the game is the Igla (SA-18.) You can barely see them even with the Shkval, and realistically, they could hide anywhere in building, ditches, anywhere, and just wait for you to get close. Like silent assassins.