In Star Trek: The Next Generation, Wesley Crusher is shown to be a genius. In addition to this, he had a great deal of Starfleet experience, as he was a sort of intern on the flagship of the Federation. All this should make him an ideal Starfleet cadet candidate, yet when it was time for him to apply, it was treated as though it was likely Wesley would fail the acceptance exams.
Contrast this to Nog in Deep Space 9. He's not shown to have an exceptional intellect or physical capability. Commander Sisko recommends him, but surely Wesley had Picard's recommendation as well. And yet Nog has no problem passing the acceptance exams (setting aside Quark's interference), and ends up a cadet.
Did the exams become easier between the two candidates' applications? Did Starfleet give Nog preferential treatment as one of, if not the, first Ferengi applicants to Starfleet Academy? If so, is it Federation policy to make it easier for applicants from non-member worlds to get in to Starfleet Academy?