Some Derby angles that still can be considered....many have recently gone by the wayside with modern breeding and training procedures but a few remain relevant to the point of consideration with other factors:
1. Winner will have 5 or more lifetime starts prior to Derby
2. Winner will have at least one 3yo prep of 8f or longer.
3. Winner will have at least one race at 2yo.
4. Winner will have at least 12 points in DP (Animal Kingdom went against this in 2011 with only 8...before that Middleground in 1950 had 12.
Obviously none of these should be viewed as absolute and are useful after considering all other factors such as form and breeding.

you can talk all you want about the others but it will be only one of the two horses that will win this race.

Here's the excerpt from the book: Jack, From Grit to Glory (the story of Jack Van Berg)

In the buildup to the race, Jack recalls a point-blank, if not rude and ignorant question asked him by famed ABC television broadcaster Howard Cosell. “Jack,” Cosell said, “why would you bring a New Mexico-bred to the Kentucky Derby?” To which Jack replied, “Howard, he can’t read and he don’t know where he was bred, but he can damn sure run.”

A classic quote indeed!!

1. Losing relevancy after Big Brown and new prep schedules.
2. Irrelevant because you probably can't eliminate 3 entrants in the past 5 years.
3. I believe this will fall in the next decade, though not this year. Again, it's of minimal value because we only see maybe 1 a year try it, and that one is typically a brilliant miler.
4. Probably a good pedigree angle and more useful than the dosage angle in 2015. 20 years ago DI could eliminate contenders, but now most will qualify. You have to take a stand against American Pharoah if you're a Dr. Roman disciple.