Star Wars' dialogue was filled with emotion, good form, and conceptual significance. Dialogue from the prequels, on the other hand, was boring, awkward, and stupid by comparison. It's sad to watch the many good actors of the prequel trilogy trying to deliver those lines well (it wasn't possible). Ewan McGreggor came the closest to delivering every line well. The actors in the original trilogy had an easy time by comparison.

Were the OT's lines dorky and crass at many points? Sure, and, in that specific, superficial sense, a lot of the crap lines from the PT will seem similar on that basis. But, they still managed to be genuine, heartfelt, and realistic to the degree where their dorky and crass nature promoted likable characters (and that makes all the difference).