I'm not really sure why GM's make these promises in the first place (maybe so a team drafting behind them won't interview the player, fall in love with him, then try to trade up a few spots to steal him)?
But to be fair, Pierce was supposed to be a top 3 pick (
example here,
here,
and here), and after #5, if we exclude Dirk (because foreign scouting hadn't really taken off yet), Hughes was arguably the best player taken between 6 and Rashard Lewis at 32 (though Jason Williams or Al Harrington fans might disagree with that).
Most other years, that's probably a pretty safe promise. He was probably around the 8th best player taken in that entire draft. If anything Larry Brown seems spot on with his player analysis, from the article it says he ranked Pierce #2 and Hughes no worse than #8. That looks pretty spot on to me