Every single player selected today has a lot of talent and promise. All have the potential to become quality pros. Some are riskier than others. These are the workout warriors.
Unrefined players with physical tools are often tempting. They leave more room for imagination than their more developed counterparts. There is less guesswork involved with polished prospects. They are closer to their respective ceilings, which makes these ceilings easier to project. The player who still needs development might become an out of this world player. It is possible that once this player puts it all together, he will be an all-world prospect.
The problem is this kind of player still has a lot of work to do just to reach the point the polished player is at today. Many never make the leap and never end up matching the production of safer picks with arguably lower ceilings.
Reggie Bush is a perfect example. There may be no player with greater physical gifts in the past three decades of the NFL. While he has been reasonably productive for the Saints and established himself as a dynamic weapon, Bush has not established himself as an elite running back. This is because he has not refined his game enough to improve the key areas of the positon. He lacks the necessary vision and patience. Instead of finding and hitting his holes, he tries to turn the corner and run for a touchdown on every play. Against college level, this was easy. He finds much less success doing this in the pro game. There are times when he breaks one, but it is not so simple against the elite athletes of the NFL. If he was more willing to run between the tackles, find his holes, and take 4 and 5 yards games, he would be more effective when he tries to break it outside. Defenses would then have to focus on preventing him from breaking a big play running hard inside, which would open up other areas of the field.
This is the danger of selecting players whose biggest asset is athleticism. Invariably, a number of players shoot up the Draft boards months after they play their last down in college. This is based on tests of athletic ability like the Combine and pro days, not tests what really matters on the football field like game film shows. Percy Harvin is a posterboy for this year's Draft. Although he was very productive in college and possesses superior athletic ability, game film shows he does not run good routes, which is how receivers get open in the pros. Unless he improves this, he will never amount to more than a gadget player in the NFL. Refined receivers like Hakeem Hicks who run quality routes and have good hands have a better chance to succeed because they already have these traits. They do not need to develop the attributes.
Some physical talents do refine their games. However, it is often safer to take the refined guy over the "high upside" player. Teams get reminders every single year, but many never learn from it.