The NFL draft is the worst of all the major sports drafts imo.
... What? THe NFL draft is, clearly, the best draft, which is how they can split it over 3 days on prime time. 45million viewers watched the NFL primetime draft last year. Compare this to 2.5million viewers of the NBA draft in 2014. Heck.. compare this to 10million viewers who watched the clinching win in the NBA championship last year.
And it's not some mystery why the NFL Draft alone is more popular than the championship games of every other professional sport. Nearly every player in the NFL draft in the first 3 rounds is a known, proven commodity, and the majority of those players in rounds 1 and 2 make meaningful impacts on their team in that first year. The NBA draft has dramatically improved since the college requirement was established, but it's still largely difficult to predict outcomes of any player outside the top 5, which is why lottery picks have such an imbalanced weight.
The effectiveness of the draft immediately impacts the product on the field/court as well. In the NFL, there are only a small handful of cases where teams tank a season for a high draft pick.. Indianapolis tanking for Andrew Luck is basically the only contemporary example of a team that is seemingly tanking a season to draft a single player. Yet, in the NBA, this happens almost every year, with 3 or 4 teams who have a race to the bottom, because after those top 1 - 3 picks, the value of a draft pick drops considerably. Compare this to the NFL, where teams regularly trade down from a 1-5 pick because you can still get all star quality talent at pick #10 or 20, or two 2nd round picks.
This isn't to say that there aren't busts in the NFL, of course there are, but more often than not, players can be properly evaluated in the NFL draft and a players' success and value to a team is easier to judge, making for far fewer busts and a lot more interest in the draft.
I mean, the fact that the NFL draft has 4x more viewers than the clinching championship game in the NBA and almost 25x more viewers than the NBA draft is a testament to this.