I have to disagree strongly with the others that have posted on this thread. Laverneus Coles is a player that is clearly headed downhill and appears like he might be near the end of his career. Eddie Royal, while a disappointment this year (which I blame largely on a new, inferior QB and a new, heavily run-oriented offense), is a very young receiver who has a long career ahead of him. He caught more than 90 passes as a rookie, so we all know that he has a lot of ability, he just needs the right QB and scheme to bring it back out of him. Keep in mind that this is a dynasty league, so you have to think long-term, as well as this year.
Long-term, there is no question that Royal is the guy. This year? It might be a push or just a very slight advantage for Coles. However, if a rapidly-aging WR like Laverneus Coles is truly the difference between your team winning your league championship or finishing in 2nd, then I will personally apologize for my bad advice at the end of your season. Until then, the answer to this question is Eddie Royal.