If the ONLY process that needs to be done is to reformat the file (with 100 or less fields), yup - sort would be a good choice.
If the process needs to do other processing (i.e. read a database or vsam file), then a program would be a good choice.
Unfortunately, i have seen processes implemented using multiple passes of the data (makes a difference for a few hundred million records) so that some particular knowledge (sort, fileaid, Easytrieve, etdc) could be exploited without determining if the whole process might be better served in one bit of "code". . .
Hope this helps,