I think this depends on whether or not the Drupal 6 version is to be 2.0 or 1.0. If Ubercart 1.0 for Drupal 5 is to be converted to Ubercart 1.0 for Drupal 6, then the code should remain as close to the Drupal 5 version as can be, meaning keeping with all the dependencies. By not keeping with the dependencies than I feel the Drupal 6 version should in fact be Ubercart 2.0 as it would contain New features. One might argue that moving features provided in a different module into Ubercart are not New features since they are basically the same just Ubercart working the magic instead of them, but my reply would be that it is a New feature for 'Ubercart' itself and thus would need the version 2.0 stamp. TAPIr, uBrowser, and Workflow-ng should be converted to Drupal 6 for Ubercart, otherwise the changes to Ubercart 1.0 are too drastic to call it version 1.0 even if it is for Drupal 6.

By implementing features provided by another module inside of Ubercart opens the door to making those features better and adding features to those features. I feel unless the Drupal 6 version is a 2.0 release then no changes should be made to Ubercart other than converting it from Drupal 5 to 6.

I think I repeated myself on some points, but it's really late and maybe the different wordings will help get the point across. I hope I'm not alone in my thinking.