They are fine. There are many different styles and configurations of shoe trees. The ones you have purchased are the lower end made more for deck shoes or sneakers. They will do the job however.
Browse these links to further familiarize yourself with just a few of the different models of shoe trees available.
I use Woodlore as an example but also check out other makes.
http://woodlore.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=woodlore&Category_Code=Shoe-Trees
https://www.google.com/search?hl=en&complete=0&q=woodlore%20shoe%20trees&biw=1280&bih=522&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi
Woodlore's 'Epic' is one of their high end models though even they may not be the right shape for all dress shoes.
Study the shoes you have before buying shoe trees. Some shoes have a higher instep than others.
The Woodlore 'Epic' shown here is best suited for Balmorals, in my opinion whereas their regular tree is good for Bluchers.
