[quote=Windstormugly]
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? 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 ^^
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My main thing is the change of shape AND size. Changing shape, as I said before hand is as simple as saying that there is enough cartilage and space between bones to where they could naturally and easily shift from a more feral dragon stance to a bipedal one, but in turn their feet, hands, initial leg shape (with some slight adjustments here and there) and mass intake would all still be the same. But if size is being changed as well than we have a MAJOR problem, which is a big question of "where did all the mass go?" so unless we add a classic Sci-fi shrink/grow ray inside the dragon's body, it would not work all that well. 

As for the shape shifters, I'll agree that them taking only one to two shapes isn't all that much but in the end if they can dramatically change in shape like that than there really isn't too much of a reason why they can't change to other shapes as well besides them not wanting too, which would be VERY understandable because, as you said a lot of energy is being used to do such. 

Not really what I was talking about... what I'm suggesting wouldn't effect the muscles or bones too much since the change would be very minimal, main thing that could change would be the bones spacing out a bit and the muscles would hardly change, especially if they contract like you said but again that would make them very stiff in the lower body and the change would, yes, still hurt a bit (kinda like "popping" your shoulder bone) but after the initial pain it should be all good until they decide to "shift" again and it really wouldn't effect the entire body, just the legs.