I was taught in sales never to use such terms; for instance telling someone I will call them back soon. It is a meaningless, open ended term that leads to misunderstanding. Preferable is to set a time frame - I will call back next week.
At http://www.jwfacts.com/watchtower/quotes/end-soon.php there are examples of Watchtower use of soon spanning 130 years along with the other favourite imminent.