I haven't get a chance to try the ink brush yet(working today), but it sounds like it's being judged pretty harshly - as a crappy weapon - before people had the chance to find the proper play-style(or mode, as more are on the way).
It reminds me of the roller-rollercoaster. First it was "too OP" based on the couple test-fire sessions. Then once people got a bit more experienced with the final game, they considered it "garbage." Now, and more accurately, it's simply a fearsome weapon in the right hands.
So far, based on early impressions, the brush seems perfect for 'disruption play'. Sounds adept at easily getting behind enemy lines, keeping them annoyed and occupied while your teammates cover more turf or claim zones. Even its sub and special(sprinkler & ink strike I heard) caters to disruption, while you are able to stay out of conflict.
It would take really skilled brush-play to consistently get over a 1000 pts in turt war, but it could be one of those weapons that leads your team to victory time and time again(perfect for ranked!), at the expense of sacrificing your own points(only an issue for turf wars) since you'd play as mostly a decoy.
Has anyone yet found success with this weapon, or see themselves excelling at it in the near future?