I think the real problem is the script writing. The acting doesn't bother me much, and I think it goes up and down with the dialogue.

That said, the direction and writing of the OT brought humanity even through aliens. C-3PO especially provided the human touch even though he was all robot. Chewie was fittingly more of a "dog touch", as he was based on a dog, but I think the OT showed facets of humanity through aliens, whereas in the PT aliens and humans alike are a channel for the plot.

So to answer the question, YES the PT needs more humanity, but NO it doesn't need less aliens.