The OP seems to be confused about the difference between the 1DsMkIII and the 1DMkIII. It was the 1DMkIII that caused all the panic because some had a problem with focusing in some circumstances. This led to a large number of threads with titles like "My MkIII problems" and "Just got my MkIII and it has the problem" etc. The posters of THOSE threads also didn't seem aware that there was also a MkIII of the 1Ds series. As a result, there are folks who think all MkIII cameras have problems. Canon would be wise not to call the next 5D the 5DMkIII - everyone will avoid it
I did get confused. At any rate, imo, the whole MkIII or IV or whatever line is tainted. Too confusing and advanced amateurs like myself will probably avoid the entire line. Thanks for the comments though, very interesting.