My top ten as of now.
My guns in the top 30 are pretty much evenly spread, and the funny thing about the ACE 52 is that I got those 873 kills within the first two weeks of playing, and then seriously never touched the gun again. It's been more than three months and it still remained my top weapon until I just passed it with the MTAR by two kills a couple days ago. If I had stuck to that only my K/D ratio would have been insane.
Even though I think the gun is great, I still don't think it needs to be touched, or that it needs to be weakened. Mainly because the variety in guns I see people use online show that there is no one all-ruling gun in BF4.
I actually hope they keep things just the way they are, and never make any gun worse.
Edit: I just see that my Claymores fell out of the top 10, which are also close in like with my weapon kills - probably because I don't play Domination as much as I used to, but I put them in all the nastiest spots to the point I get multikills with them.
I'd love to go on a long streak like that with a PDW or even an Assault rifle when I run solo. Not only is it rare to even see a support guy, but it seems like they don't even drop ammo for themselves. I put the callout for ammo already when I'm halfway empty and still support people don't react to it.