Those are pretty awful. US Mint frontloaded just about all the good parks so from now on you are going to see some obscure parks with redundant and/or uninspired designs.
They haven't selected the order of the sites, or chosen the "better" ones.
They are in the order of when they first became a national park/monument, beginning with Arkansas hot springs which is the oldest (first established by congress in 1832).
Site Selection Process
"The United States Mint will consult with the Secretary of the Interior to ensure appropriateness of each of the 56 national site recommendations based on their natural or historic significance, and to validate the date on which each recommended site was established as a national site."
