How is this different from previous editions? The DM makes the pirate's level to be under that of the party (to present less of a threat), to make it equal to the party (to make an equal level threat) or higher level than the party (to be more challenging a threat).Even more on the particular point, the pirate's level is defined not by the pirate, but by the party.
The Party is in the forefront of the DM's mind.
It's a rare game where the pirate's existence is static. "He's 5 levels above us? Okay guys, let's fall back, go level up 10 levels. He stands no chance against us then."