Just to continue on your hoof angle discussion. A couple years ago, my mare had a subtle lameness problem that had been misdiagnosed as an upper suspensory tear. I felt that the suspensory diagnosis might be incorrect and went for a second opinion. It turned out that the suspensory was fine and that there was a slight shoeing/trim problem that was found through Xrays. Although the shoeing looked great, Xrays showed differently and a slight change in shoeing has kept the mare sound for the last two years.
I now try to Xray all the competition horses to make sure that shoeing/trim angles are correct. It also gives me a base set of xrays in case down the road a problem arises and we want a comparison set to see if or what changes are occurring.