Spiders wobble. I don't believe you can "select out" this problem as they all have some level of it. Most of the time when people say "mine doesn't wobble" or "not my Spider" it's because they don't notice the more subtle signs or they don't want to admit that the pricey little snake that they purchased isn't perfect.
With mine I only see it a little at feeding time so I don't see it lowering their quality of life.