It is true, later in his life Horowitz was not the most precise pianist, ever. Also, he developed some mannerisms, which can be annoying at times.
For some reason he was struggling with 1st Ballade for whole his life, both technically and musically. I have at least 4 recordings from different years and none of them are quite satisfying, at least to me. Sometimes I listen to them just out of curiosity, wondering how come such a spectacular pianist as Horowitz could not find some magic there, or maybe he played it so often that lost its freshness.