That's the big problem with the PT (well one of them).

As Episodes 1 to 3 they don't work, as prequels to the OT they could have worked if they were made better.

A prequel is not the same as earlier episodes of a story because it assumes prior knowledge of the story that comes later so doesn't need to maintain the plot revelations, the writer assumes you have watched the later episodes already.

To truly be Episodes 1 to 3 it would have to approach the story as if episodes 4 to 6 hadn't been made yet.