Not that I have anything to do with the WL, or that the height at WR "argument" means a whole lot, but jdbolick's comments are more accurate.
Height doesn't necessarily determine how good a WR can or will be in the NFL. Being short can be good depending on your skill set. Being tall can also be a good thing. NFL Quarterbacks typically prefer to have both smaller and larger targets for different situations. A smaller WR provides a different window. Smaller WRs typically accelerate faster and change direction faster. A smaller body type helps you get out of your break faster. That doesn't mean someone who is 6"5' or taller can't be quick. The added height just makes it harder to do so. It also seems to me that the smaller receivers tend to have better hands. That's not a fact nor do I have any evidence to back it up.
Taller Wide Receivers are typically better red zone targets. The extra height and length go a long way towards hauling in jump balls. Height is going to help most players who are running a fade route, etc. That much should be obvious. Raw height can also be intimidating to the DB who has to cover a taller WR.
Height CAN be a hindrance though. Someone basically said height can't hurt but that's not taking into account the true giants of the world. How many receivers, no, how many NFL players are 7"0' or taller? I'm too lazy to google that but I'd guess it's somewhere between 0-10 at best. At some point you can become too tall to be effective. I'm sure the reverse is also true.
If certain players magically grew 4-5 inches taller, it wouldn't necessarily help them become a better target in the NFL. It wouldn't necessarily hurt them either. A lot of it is situational, the rest is about how great of an athlete you are.
