True, I am most probably the one the lovely Jest has mentioned.
Now, tissue compaction is not that much of a problem, though what I mean as the morphing is not something they would be able to undergo often, as the change from humanoid to dragonoid? (by making their skeletal structure lengthen and widen, some parts probably springing from resting-places underneath their skin. and then filling the limbs with new tissue along with part of the old.) would apart from consuming huge amounts of energy/calories make them fairly thin until they have managed to stabilize. And here I am proposing the dragon form to be a light one. The change back would create a bodily rise in temperature as the tissue and bones compact. they would also be a bit stiff as you say, like old people who doesnt exercise and stretch.

As you say, a shape-changer normally operates on a cellular level, otherwise by using an extremely fast metabolism and "soft" skeletal structures. And I might add that every shape-shifter that is only able to do one change is not worth much as far as shape-shifting goes.

What you are talking about could possibly be classed as a rearranging of some bones and muscles, would hurt a bit, but would make them more able to perform some tasks. I agree that going from a feral dragon to a humanoid is... not advised, the amount of energy, the stress on the body. not to speak of the mind.

A pleasure to meet you as well ^^