It is pretty awful that when I search Google and "bad ballet feet" comes up with over a million sites and "the right ballet feet" or "flexible ballet feet" comes up with between eight and two results. It is a cultural bias that persists in the world of ballet, yet many many famous ballerinas did not have 'the right ballet feet', Margot Fonteyn, a legend, for one. But, if you have bad ballet feet, or think you do, let's talk about the right pointe shoe.
A less flexible ankle joint, requires a pliable pointe shoe usually with a lower vamp, unless the toes are long.
There are so many shapes and styles of pointe shoes. You must take time to try many on, and be fussy. Even if one type feels good, try on all that are in the category of "more pliable".
If a shoe feels good (none of them really feel GOOD), try on a half size shorter/longer/wider/narrower, just to be sure.
Do a demi plie in each one, making sure that your toes are not completely squished into the box, with pain. You need some "squish" room, because the feet spread when you plie.
Be sure to take your toe protectors to try shoes on. Take tights to put on your feet. With one foot (standing on flat with the other) press up onto a pointe position in a try-on shoe. See if your foot places onto the platform easily, and feels the whole shoe, except for the middle of the sole, or shank, which will not bend yet.
Use something for a barre and rise up onto pointe with both feet. Make sure you can rise onto the platform completely.
The right feet for pointe shoes, are feet that have been wisely prepared for pointe. Special foot exercises can be done for months before a student is ready for pointe classes.
As a matter of fact, there are NO BAD FEET IN BALLET. Except maybe those feet that have had no preparation with special training, for strength and flexibility. Get the right exercises and plenty of practice for your ballet feet, and you'll be ready for the right pointe shoe.