Cube bike cassette wobble
Wobbling cassettes should be absent from, not present on, every bike. It is possible that the wobble is caused by worn splines on what might be a soft (aluminium, as opposed to steel) freehub. I myself recently blogged about such an issue at http://bit.ly/HubTrouble .

The wobble might instead be a result of an incorrectly seated lock-ring, or a missing spacer from behind the cassette (in which case you might find this link of interest: http://bit.ly/CassetteIssues)