I said this when he was signed and I'll say it again: Rondon will not be his most effective with his back against the goal, out on an island, and definitely not spending most of his energy running around without the ball because he has to account for being the only man up front without a lot of support.
Rondon is a goal-scorer because he works hard inside and outside the box and as a result is often in scoring position, is a load to deal with because of his strength, and is very good in the air game. Read that description over. How many EPL teams would want someone like that? He's not going to get the ball 35-40 yards out and dribble past the back 4 and score. If you feed him, he'll score, he'll be ready. But what he's being asked to do at WBA? That's not going to result on a lot of goals. However, I've seen him have a positive impact on TP's gameplan even if he only has 3 goals so far.