On the plus side, Dubai Sky appears to be developing and maturing at the right time. He has enough tactical speed and flexibility to be placed as his jockey judges best, and his pedigree suggests at least a solid possibility of getting 10 furlongs, a distance at which Twirling Candy placed twice in Grade I company. The fact that he is from the family of the great Affirmed certainly doesn't hurt anything.
The down side is that Dubai Sky has yet to race over dirt, and the Kentucky Derby is a tough place to try this for the first time. The field is invariably large, the jockeying for early position is fierce, and a horse that doesn't get an ideal spot in the early going may find itself taking a lot of kickback. One need only recall how Zenyatta floundered in the early going of the 2010 Breeders' Cup Classic (USA-I) at Churchill Downs to get an idea of how a horse unused to the conditions may respond. The fact that Dubai Sky's connections chose to start him out on grass -- not the usual path for a well-bred colt whose pedigree doesn't scream "turf" -- may also say something about where he is best suited.
Twirling Candy was a pretty versatile sort, winning on all three surface types, and it may be that Dubai Sky has the versatility to do the same. This performance was not in the same league with those turned in by American Pharoah and Dortmund in their most recent preps, though, meaning that Dubai Sky would have to improve significantly over an unfamiliar surface to be a serious threat at Louisville.
Overall, my impression of the Spiral was that this was a rather one-paced race where Dubai Sky simply slowed down less in the stretch than his competition, though to his credit he did so while racing wide throughout. He may be this year's Animal Kingdom, but my feeling is that the Sky may hit his limit if run in the Derby.