you can see the stator magnets have a gap between them and the coil. In the second image you can see that on the other side the magnets are pinched up against the coils. I am guessing that is why the axle will no longer turn freely.
Gestalt,
Has the motor only been stiff to turn since your attempt to dismantle it or was it already tight before that?
If it did become stiff during disassembly, can you remember what you did that may have caused it to become tight?
Did you by any chance try to encourage the spindle out of the housing using some "gentle persuasion" from a large mallet.
Have you tried it with the front housing refitted and tightened fully to centre the rotor correctly?
If you removed the four allen bolts on the rear which hold the stator in place, the stator could have been pulled towards the magnets and may just need to be reseated back into the correct position again.
I'm basically just clutching at straws here, as it's very difficult to see what might be causing the problem without being able to closely inspect the motor.
It might be worth taking it to a local garage or machine shop for a second opinion, as someone who regularly deals with mechanical problems will probably be able to locate the problem straight away.
Alan