VNA,
I was an instructor myself and have had a brief spell flying the heavier stuff, so I am speaking from experience.
I do agree with alot of the points you make, working as an FI is a great experience and it is better to be instructing that not flying at all.
But for completing a type rating IFR currency and a bit of time of some higher performace types will be far better preparation than several hundred hours of VFR instructing. As said the usefulness of instructional hours to employers is the fact your hours will allow you to meet insurance requirments and reduces your time to command. Fair enough get the no applied instruments restriction lifted and then instructing will allow you to maintain IFR currency.
Amex has hit a very good point, do too much of one thing for too long and you start to think you are getting good at something, but if you don't keep progressing then you can fall into a comfort zone and it can get harder to get back into the learning zone.