For the SAS 9.2 release, we do not have a "sort by response" option for dot plots. However, you can work around this by presummarizing your data, sorting it by the response value, and plotting it in sgplot using a a scatter plot to simulate a dot plot by using options like the following:
proc sgplot data=sorted;
yaxis grid;
scatter x=freqcount y=category / markerattrs=(symbol=circlefilled);
run;
Let me know if this works for you.
Thanks!
Dan