I agree with your disagreements. People are accustomed to fractional stars on product ratings, so rounding 4.5 up to 5 would be misleading. If I see a full five stars on something, I'm inclined to wonder if it's only gotten a few votes from the seller's buddies so far. I could see rounding to the nearest half-point, as long as the star icons match. The icons should match whatever numbers are displayed.

And skipping the ratings that have gotten no votes yet would be weird and bad.