Can anyone think of an easy fix for this that does not involved tearing it apart?
Add a shim under the bottom hinge on the door side. Cant tell if the top hinge is binding or not. You need to determine if the door or body hinge mounting area is moving. Hopefully not both.
Seems to me the door is to far forward. It looks like it needs to move back. Using shims may help it. Hope the hinge mounting are on the body side isn't cracked and bending in.
If it is you can remove the door and repair the area. Hopefully.
Tim, in effect, the hinge pin is too far forward. If you can undo the hinge at the pillar, a tapered timber wedge could be inserted between the hinge and the pillar, thick side out. This may or mat not upset the height of the striker at the B pillar.
Hope it works for you.
Allan from down under.