Do I wait for the ipod touch 6th gen or do I buy the 5, right now I have a 4g?

Yes, having a patience for the 6th gen ipod can make a great help because this latest release has a very large amount of updates and new features, thus, buying the 5th one can also be great, still it's newly and has a lot of bugs fixes than buying 6thgen that is not yet updated in bugs, tracks, etc.