I've always been a fan of Robson in the sense that like others have posted already, you know what you're going to get from him. The man knows his limitations (just like all men should according to Detective Harry Callahan).... In saying all of that, I would assert that Robson probably had his worst season in first grade in 2015. He made some uncharacteristic mistakes at times, took some really poor options on occasions.... perhaps it was just an anomaly, maybe the result trying too hard (again, uncharacteristic of him) when their season was stuck in 2nd gear in the early to mid part of the season...
In any case, I imagine he ain't costing the Warriors a fortune and he is as sound a defender as you'll find in the halves across the NRL...