Not surprising... limit your pairs of shoes. They occupy a lot of space in your suitcase and add weight that you may have to pay for upon check-in.

More important, don't waste the space available INSIDE those shoes. Stuff shoes with belts, socks and undergarments. This will save space and help shoes keep their shape. (Roll belts, starting with tip and ending with buckle. The buckle will lay along the inside ridge of the shoe.)

 
Always pack shoes on the bottom of your suitcase near the wheel base. Use extra undergarments that did not fit inside shoes to fill in the gaps between pairs. This gives you a very sturdy base to pack the rest of your clothes. (Clothes you rolled, of course.) If you pack those shoes on the top, their weight will pull them to the bottom of the case, wrinkling everything on their way.

Keep those wrinkles away and always... Keep those traveling shoes ready.