I have made a Dragon Shape Build just to test this for everyone and i have came to a conclusion that it hasn't been customized at all. Here's a website showing everything about
Dragon Shape. The only thing that would be customized is that Elemental damage from weapons merge with dragon form but here's how it works:
In Dragon Shape you have 3 kinds of attacks. All of them deal basic physical damage but elemental damage can be added to them if you wield a weapon. Main hand weapon covers 1st attack, Offhand covers 2nd attack, and 3rd attack stays unchanged. Therefore in order to add elemental damage to Dragon Shape damage you have to dual wield weapons but even with it you can't cover 3 kind of attacks Dragon has. Also, On Hit: Unique Power doesn't merge with Dragon Shape meaning that only the damage on the weapon merges(2d12).
Another thing that was changed is that you can't shape shift wearing shape cloak/item.