Interesting comments. While I agree you cannot teach someone 'aptitude' for the job I do beleive that coaching in interview technique can be beneficial.
You can have a guy or gal who has everything it needs to do the job but just goes to pieces in an interview. We once had an ATSA who fell at one hurdle in the interview process. We sent him on a two day assertiveness training course. He is now just about to complete his Approach Radar Course.