If you have seen me play sniper I allways use claymore to protect myself or flags, not to throw just casually around.
This way it enables me to snipe as I want, and I can instantly change location if i see a clay go off, so that I can snipe from a new more safe location.
Doing this I went 133 - 8 in 4 rounds today, averaging 34.25 - 2 per round, and I also played pretty agressive going for flagcaps and such.
I mean claymores is very powerful, maybe too powerful, but there are also lots of other annoying things in Bf2, such as Support nade spamming all the time, F2000 users with flashbang, the "invincible" J10, the super accurate G36E and so on.
Being good with any of those things is sure to piss people off no matter what.
I would gladly change out the clays for a more powerful handgun on the sniper, but since they are allready part of the kit, I use em simply put.