Actually it depends...Semimetallic pads
in general (there are some variances) are supposed to wear the rotors faster since, as the name states, they are metallic, just not entirely metallic. Metal to metal contact creates more friction and thus more wear, but in the case of the ceramics, as stated by the
Shop Manual for Automotive Brake SystemsBy Clifton E. , they dont dissipate heat as quickly as semimetallic so the heat stays within the rotor, caliper and brake fluid, which combined with what they call improper pad/rotor configuration, may cause rotor warpage, which is basically what you claim. The info may be found here
http://books.google.com.pr/books?id=...sult#PPA159,M1
Anyways, a lot of people have used them without problems, it just depends on your taste and
keep in mind that not all semimetallic pads or organic or ceramic pads are made with the same recipe, so because one may be worthless does not make all within the general category worthless