Well, let me answer my own question, after a half hour on the phone with Apple. Indeed, for some reason, they removed the inclusion of file size in the finder window when attaching files to e-mail. However, the work around is, if you choose the column view, at least when you click on a file you will get the info about that file, which is quicker than having to do "get info" for every file you're considering attaching. Why oh why do they go backwards when they upgrade operating systems?? Hope this at least helps someone else.