I'm not sure what the most broken builds is and how to define that... for me that means, I dont have to throw 1k+divs to clear some of the hardest difficulty. I think a broken build is where it has a high ceiling and also that the build does the carrying... much more than your wallet.
I do have a build that seemed that way so far that I'm testing. I spent 250 div on a gemling legionaire totem-er and it's clearing things super well. I got bored of my lvl 97 ice shot ranger too and made this instead, I feel like it's 3x stronger than my ice-ranger at this price range. additionally you can scale it hard, but the items become very expensive.
I'd say builds that will probably get nerfed after this patch or changed. I think totems are in a great spot and feel like they will get heavily nerfed after this patch.