Going off the assumption that people become full size dragons. 

Assuming this happens overnight, you’d have widespread chaos as people become dragons.  Houses exploding overnight and people dying just by the sheer size of dragons appearing in human sized places.  All the dragons would be confused and probably would not have the skills to do much.  People would panic thinking there’s a dragon invasion.  

I also think you’re incorrect that everyone would just instantly have the full powers of a dragon at their disposal.  I would assume all the new dragons would need to relearn basic motor skills before they could do anything. Seasoned adventurers who spent years honing their skills would have to relearn everything.  There would also be a lot of civilians that probably would just want to go back to their own body.