Rom is a team dependant predatory type of striker. His style is to lay in wait for the right ball, pounce on it and power it through the defence and into the net. If he does not get the right ball, then he either has to stand around like a spare part, or trot about in his zone, shaking up the defence until the ball finally comes, thus giving the impression of a lazy player. Consider the way lions hunt versus cheetahs. The lions depend on the majority of the pride driving their prey into the path of the few awaiting attackers hiding in the grass. The cheetah uses speed and skilful manoeuvring to get the job done, (thanks David Attenborough).Plus all this talk about a striker being lazy.
If you're the only striker up there, you have to choose when to run and put pressure on the defenders. You can't do that all the time.. It would be different with two strikers or if your midfield would play really close to you. Something which didn't happen last season.
Occasionally, getting frustrated, he will try and create something himself, but then ends up out of position, like on the wing, feeding the ball into the box where the predator, (HE) should be. You will see this in other teams as well, where the striker is starved of passes.
Of course, if said striker loses interest (as I believe was the case with Rom last season), then he will not be concentrated enough to get himself into the right predatory position in the first place.