Sorry for the delayed response. Just came across this thread.
This type of stuff happens to me. I've been diligent in inspecting the suitcase after long flights, and in the most serious cases and if convenience allows, I will file a claim with the airline while at the destination airport. This is usually not convenient, and I will "consolidate" issues with a trip flying back to my home airport (and preferably from a business class flight), where I can give up the luggage for the week to fix the dents.
Rimowa stores can also arrange for periodic dent fixes at a fee. Taipei stores will fix dents for free from suitcases bought within Taiwan, and charge a modest (US$30) fee for those bought outside and I suppose, off warranty.