As with everything, a solid player will do fine no matter what spec you are in. If you have a strong spec preference, stick with it, try different approaches and see what works for you. For operations, either spec can work, if you are willing to make it work.
In a lot of cases, I prefer ruffian for dailies. Point Blank Shot the strongest mob in a group from stealth with KO, use shrap bomb, drop bushwhack, thermal grenade... with a dps companion, things tend to be dead by this point or maybe you blaster whip a survivor, and then brutal shots if one refuses to die. I rarely ever use vital shot and try to dot spread with weaker mobs; it's too unreliable and slow to set up and take effect.
Several dailies have champion mobs that aren't immune to stuns, which is a lot of fun with scrapper... the second back blast knocks them down again. So much fun. Blood boiler and vital shot are unchanged in 5.4, so whatever you are experiencing isn't that... it's probably the flying fist and fletchette nerf.
Ruffian in PvP ranges from challenging to very challenging without a healer, as you just get obliterated when focused. Still, it is possible to put up very solid numbers that aren't just dot fluff. You have to be very dogged about focusing and following tank / healer combos, for instance. Shrap bomb is annoying and fun, but you can not just keep throwing it and hope for good numbers. It won't happen.