Don't worry about wobble. The power jack is not mounted directly on the motherboard.
Back several years ago most laptops did mount the power jack to the motherboard and it could easily get damaged by force. If the power jack was loose it meant it was broken off the motherboard.
Engineers got smarter and now most netbooks and laptops have the power jack mounted to a cable with a simple connector on the end that plugs into a matching connector on the motherboard. The looseness you feel is a result of the power jack itself not fitting perfectly snug into a matching feature in the bottom housing. The bottom housing is just a molded plastic part and there is some variance from one to another.
Here is a picture of a 10V I found through google.
http://www.flickr.com/photos/dandydanny/4071841482/in/set-72157600098124884/It may be hard to see, but the power jack for this model is on the left side. You can see the cable going from the power jack to the motherboard.
The new 1012 model has the same basic design, but the power jack is just on the back now.
Maybe I lost some people, but the point is that you don't need to worry about wobble.
It isn't what you think it is. The connection is probably just fine, the whole jack housing can just move a bit with these new designs.
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