I see no reason why 24-70 is silly on a crop.
A) I don't think the Red line looks silly.
B) It is not heavy.
C) The coverage is perfect on a 60D for shooting kids, portraits and models. Also it did pretty good shooting the bridge image below, was plenty wide enough. I did not really miss the 17-50 Sigma that I replaced.
I also use a 135mm F2.0 on my Crop, again, I don't see any problem here with shooting the model below.



