Should Instructional Designers Wear Many Hats?

A Training and Instructional Design Professional from Greater San Diego area asked:
Are instructional designers experienced trainers? As a former training manager I found it interesting that few people applying for ID positions had little to no stand-up training experience. The lucky few that had it, had gained it through work experience rather than as part of their college curriculum. Why not make a class in ‘training in the corporate environment’, including fieldwork, mandatory for a degree in Instructional Design?
Here’s what I think:
With winds of science and technology, tall ambitions, cut throat competition, and high expectations, the field of instructional design seems to get carried away in all sorts of directions like:
– Training
– Graphic Design
– Programming
– Scripting
– Business Development
– Sales
– Marketing
– Even Technical Writing
While its very good to have one or more or even many of these skills, such requirements should not be imposed on every instructional designer. When an instructional designer possesses one or more of these additional skills due to sheer passion, dedication, and/or self-drive, then that person is able to bring about a certain signature originality, and innovation, into each and every piece of work they commit to, due to their sheer personal level of motivation and imagination, and involvement of heart and soul in this field.
But when such additional skills become a compulsion on an instructional designer, they suck away the juice and originality from even the best of instructional designers, who may not have any other skills, and yet have a very wonderful skill of articulating their imagination into fresh, experimental and even disruptive or path-breaking or revolutionary designs.
Imposing a public-speaking skill like Training on say for example, an otherwise introvert professional who may be an excellent instructional designer on his or her desk, burdens him or her and takes away from his or her ability to contribute the best towards what he or she is really passionate about. Imposition has never worked for anyone. It can create Jacks of all Trades and Masters of None. And while that may work for the short-run, they create a reputation of poor quality output in the long-run.
All of the above fields can be options to pursue for those who feel really curious and passionate about the idea of exploring more, and combining one or more skills to offer a sort of one-stop-shop service provision ability. Yet such an expectation must not be imposed on one and all, many of whom may simply not be a cut out for it, who can get demotivated and whose productivity can fall, just like what happens to a multi-talented person when his or her wings are continually clipped. 
A cliched analogy is love. One does not have to be in love to imagine and experience what love can feel like. Similarly, one does not have to be a teacher or a trainer to carve a niche in the field of instructional design. For all we know, most instructional designers may be imagining themselves in the shoes of the average, dreamy, lost, silent and bored student, imagining what kind of instructional design and delivery of education would have fired the imagination of this student. What if I was that student? What would I want to see and receive to increase my thirst and motivation for knowledge, retention, and recall?
I must admit I was one of the lucky few who started my career with 6 months of training Final Year Degree Engineering students in an Engineering Coaching Class. When I used to get scheduled for back-to-back 5-hour lectures in a week-long crash course, I had no time to sit and design and document. I just had enough time to memorize cues for large sequences of content, collect and be ready to showcase as many real-life examples across concepts, equip students with techniques of retaining and recalling the large chunks of information, and last but definitely not the least, hours and hours of study to be so prepared on the subject that no matter what out-of-syllabus questions my students came up with, the logic to construct the answer was at the tip of my tongue at all times, so that I wouldn’t fall short in the eyes of a 300-strong audience. 
So I am not really in favor of the idea of additional compulsory Training Skills or Experience amid instructional designers, even though I agree that it can be an optional and kind of good-to-have skill, especially if there is a job offer that requires a professional to be both an ID as well as a field-trainer.