I can't see microwaving improving the taste, it can only take away from it. It may affect certain blends more than others. Where I live the RH is always low and therefore is not a problem drying out tobacco. Why risk it?
I've tried running a fan into my ashtray of tobacco, that really doesn't work any faster than leaving to sit.
But even my fluorescent desk lamp which isn't nearly as hot as a traditional light bulb turns a half ounce of a fresh blend crispy in a few hours.
Strangely enough I still had a decent amount of condensation in the bottom of the chamber with this crispy tobacco. The feel of it is deceptive and can still hold quite a bit of moisture, I've noticed.
The way my memory works for the past few years - I would try your microwave experiment, wander off, and find it in there the next morning. Then I would have something new to wonder about, like why is it in there??