He is frustrating because he could be so much better if he just used his brain a bit more.
He tends to react to play rather than anticipating it and this often means he is half a yard short of where he should be. Gayle is a master of anticipating balls into the box and, even though 9 times out of 10 they don't go where they should, he just keeps putting himself in there until he gets his chance. Rodriguez, on the other hand, seems to react to the ball into the box and try to get on the end of it rather than put himself where it should go.
This is why Gayle will almost always outscore him from open play.
If you look at Murphy's goal last night, Murphy had a lot of work to do, and held onto the ball for quite a while, before pulling the trigger yet JRod was not even in shot until it was in the back of the net. Gayle would have been busting a gut just on the off chance of a rebound.
What Rodriguez is though is a nuisance. He puts himself about and never shies away from being involved, it's just his poor anticipation that keeps him on the periphery at times. Can't half take a penalty mind, which is a massive skill in itself. Norwich missed something like 5 from 6.
I wish he'd chop that bun off though, he's constantly fiddling with it and it drives me crackers!