First of all, we are talking about weapons being overpowered, not the scope. If people feel the IRNV should not be a part of the game, I don't blame them. It's sort of strange to play a game like this and then shoot at lights. Like I mentioned before, I have no issue with it or without it. I'll be fine. Of course in the mean time if it's a legit part of the game and it gives me an advantage, I will certainly use it. The only reason I wouldn't is if I played games that outlawed their use then I would practice without it. BTW...as I mentioned, I played without it for the first 3 weeks. My game has picked up some since using it (stat wise), but for most of the time I pick out players before I scope so it's not that big of a deal. The only time it really comes in handy is at choke points when I know a guy is around a corner waiting to pop out for a shot, and there are tons of environmental things flying around. That is where it gives a huge advantage.
As for specific guns being OP, that is a non stop issue. Either they need to make every gun exactly the same or you are always going to have people complain. Honestly, I think the weapons in this game are pretty well balanced. I can think of 3 in each class that has certain advantages. Yet most people will always pick the best TTK. That is why the 240B and PKP are used for Support the most (they swap TTK at about 40m), AEK and F2000 for assault (I actually think the AEK will be used a lot more when they fix the stat page), and the M4 and A91 for Engineer (was the SCAR pre nerf, and many people still use it). Yet I admit I like some of the other weapons and don't feel overmatched using them at all. The M60 is very accurate with lower recoil (some people love the M249, I don't get it but to each their own). The M416 and M16 weapons have fantastic horizontal recoil, so I do use them. The only area I don't stray much is Engineer. Pre nerf, the SCAR. Post nerf, the A91 (although I may start using the M4 some more).
I really don't see much reason to touch any of the guns other than maybe buffing a few to make them more viable. Thankfully they are buffing the AN-94. I just hope they don't go crazy like they did in BFBC2 (which also was a buff from a patch).